PageRenderTime 67ms CodeModel.GetById 18ms RepoModel.GetById 1ms app.codeStats 0ms

/lib/underscore/index.html

https://bitbucket.org/worldsayshi/master_thesis-gui
HTML | 2382 lines | 2168 code | 213 blank | 1 comment | 0 complexity | 6a23b26a6763122aa1bebc1d2f157396 MD5 | raw file
    

  1. <!DOCTYPE HTML>
    2. 

  2. <html>
    3. 

  3. <head>
    4. 

  4.   <meta http-equiv="content-type" content="text/html;charset=UTF-8" />
    5. 

  5.   <meta http-equiv="X-UA-Compatible" content="chrome=1" />
    6. 

  6.   <meta name="viewport" content="width=device-width" />
    7. 

  7.   <link rel="canonical" href="http://underscorejs.org" />
    8. 

  8.   <link rel="shortcut icon" href="favicon.ico" type="image/x-icon" />
    9. 

  9.   <title>Underscore.js</title>
    10. 

  10.   <style>
    11. 

  11.     body {
    12. 

  12.       font-size: 14px;
    13. 

  13.       line-height: 22px;
    14. 

  14.       background: #f4f4f4 url(docs/images/background.png);
    15. 

  15.       color: #000;
    16. 

  16.       font-family: Helvetica Neue, Helvetica, Arial;
    17. 

  17.     }
    18. 

  18.     .interface {
    19. 

  19.       font-family: "Lucida Grande", "Lucida Sans Unicode", Helvetica, Arial, sans-serif !important;
    20. 

  20.     }
    21. 

  21.     div#sidebar {
    22. 

  22.       background: #fff;
    23. 

  23.       position: fixed;
    24. 

  24.       top: 0; left: 0; bottom: 0;
    25. 

  25.       width: 200px;
    26. 

  26.       overflow-y: auto;
    27. 

  27.       overflow-x: hidden;
    28. 

  28.       -webkit-overflow-scrolling: touch;
    29. 

  29.       padding: 15px 0 30px 30px;
    30. 

  30.       border-right: 1px solid #bbb;
    31. 

  31.       box-shadow: 0 0 20px #ccc; -webkit-box-shadow: 0 0 20px #ccc; -moz-box-shadow: 0 0 20px #ccc;
    32. 

  32.     }
    33. 

  33.     a.toc_title, a.toc_title:visited {
    34. 

  34.       display: block;
    35. 

  35.       color: black;
    36. 

  36.       font-weight: bold;
    37. 

  37.       margin-top: 15px;
    38. 

  38.     }
    39. 

  39.       a.toc_title:hover {
    40. 

  40.         text-decoration: underline;
    41. 

  41.       }
    42. 

  42.       #sidebar .version {
    43. 

  43.         font-size: 10px;
    44. 

  44.         font-weight: normal;
    45. 

  45.       }
    46. 

  46.     ul.toc_section {
    47. 

  47.       font-size: 11px;
    48. 

  48.       line-height: 14px;
    49. 

  49.       margin: 5px 0 0 0;
    50. 

  50.       padding-left: 0px;
    51. 

  51.       list-style-type: none;
    52. 

  52.       font-family: Lucida Grande;
    53. 

  53.     }
    54. 

  54.       .toc_section li {
    55. 

  55.         cursor: pointer;
    56. 

  56.         margin: 0 0 3px 0;
    57. 

  57.       }
    58. 

  58.         .toc_section li a {
    59. 

  59.           text-decoration: none;
    60. 

  60.           color: black;
    61. 

  61.         }
    62. 

  62.           .toc_section li a:hover {
    63. 

  63.             text-decoration: underline;
    64. 

  64.           }
    65. 

  65.     div.container {
    66. 

  66.       width: 550px;
    67. 

  67.       margin: 40px 0 50px 260px;
    68. 

  68.     }
    69. 

  69.     img#logo {
    70. 

  70.       width: 396px;
    71. 

  71.       height: 69px;
    72. 

  72.     }
    73. 

  73.     div.warning {
    74. 

  74.       margin-top: 15px;
    75. 

  75.       font: bold 11px Arial;
    76. 

  76.       color: #770000;
    77. 

  77.     }
    78. 

  78.     p {
    79. 

  79.       margin: 20px 0;
    80. 

  80.       width: 550px;
    81. 

  81.     }
    82. 

  82.     a, a:visited {
    83. 

  83.       color: #444;
    84. 

  84.     }
    85. 

  85.     a:active, a:hover {
    86. 

  86.       color: #000;
    87. 

  87.     }
    88. 

  88.     h1, h2, h3, h4, h5, h6 {
    89. 

  89.       padding-top: 20px;
    90. 

  90.     }
    91. 

  91.       h2 {
    92. 

  92.         font-size: 20px;
    93. 

  93.       }
    94. 

  94.     b.header {
    95. 

  95.       font-size: 16px;
    96. 

  96.       line-height: 30px;
    97. 

  97.     }
    98. 

  98.     span.alias {
    99. 

  99.       font-size: 14px;
    100. 

  100.       font-style: italic;
    101. 

  101.       margin-left: 20px;
    102. 

  102.     }
    103. 

  103.     table, tr, td {
    104. 

  104.       margin: 0; padding: 0;
    105. 

  105.     }
    106. 

  106.       td {
    107. 

  107.         padding: 2px 12px 2px 0;
    108. 

  108.       }
    109. 

  109.       table .rule {
    110. 

  110.         height: 1px;
    111. 

  111.         background: #ccc;
    112. 

  112.         margin: 5px 0;
    113. 

  113.       }
    114. 

  114.     ul {
    115. 

  115.       list-style-type: circle;
    116. 

  116.       padding: 0 0 0 20px;
    117. 

  117.     }
    118. 

  118.       li {
    119. 

  119.         width: 500px;
    120. 

  120.         margin-bottom: 10px;
    121. 

  121.       }
    122. 

  122.       code, pre, tt {
    123. 

  123.         font-family: Monaco, Consolas, "Lucida Console", monospace;
    124. 

  124.         font-size: 12px;
    125. 

  125.         line-height: 18px;
    126. 

  126.         font-style: normal;
    127. 

  127.       }
    128. 

  128.         tt {
    129. 

  129.           padding: 0px 3px;
    130. 

  130.           background: #fff;
    131. 

  131.           border: 1px solid #ddd;
    132. 

  132.           zoom: 1;
    133. 

  133.         }
    134. 

  134.         code {
    135. 

  135.           margin-left: 20px;
    136. 

  136.         }
    137. 

  137.         pre {
    138. 

  138.           font-size: 12px;
    139. 

  139.           padding: 2px 0 2px 15px;
    140. 

  140.           border-left: 5px solid #bbb;
    141. 

  141.           margin: 0px 0 30px;
    142. 

  142.         }
    143. 

  143.     @media only screen and (-webkit-min-device-pixel-ratio: 1.5) and (max-width: 640px),
    144. 

  144.           only screen and (-o-min-device-pixel-ratio: 3/2) and (max-width: 640px),
    145. 

  145.           only screen and (min-device-pixel-ratio: 1.5) and (max-width: 640px) {
    146. 

  146.       img {
    147. 

  147.         max-width: 100%;
    148. 

  148.       }
    149. 

  149.       div#sidebar {
    150. 

  150.         -webkit-overflow-scrolling: initial;
    151. 

  151.         position: relative;
    152. 

  152.         width: 90%;
    153. 

  153.         height: 120px;
    154. 

  154.         left: 0;
    155. 

  155.         top: -7px;
    156. 

  156.         padding: 10px 0 10px 30px;
    157. 

  157.         border: 0;
    158. 

  158.       }
    159. 

  159.       img#logo {
    160. 

  160.         width: auto;
    161. 

  161.         height: auto;
    162. 

  162.       }
    163. 

  163.       div.container {
    164. 

  164.         margin: 0;
    165. 

  165.         width: 100%;
    166. 

  166.       }
    167. 

  167.       p, div.container ul {
    168. 

  168.         max-width: 98%;
    169. 

  169.         overflow-x: scroll;
    170. 

  170.       }
    171. 

  171.       pre {
    172. 

  172.         overflow: scroll;
    173. 

  173.       }
    174. 

  174.     }
    175. 

  175.   </style>
    176. 

  176. </head>
    177. 

  177. <body>
    178. 

  178. 

  179.   <div id="sidebar" class="interface">
    180. 

  180. 

  181.     <a class="toc_title" href="#">
    182. 

  182.       Underscore.js <span class="version">(1.4.2)</span>
    183. 

  183.     </a>
    184. 

  184. 

  185.     <a class="toc_title" href="#">
    186. 

  186.       Introduction
    187. 

  187.     </a>
    188. 

  188. 

  189.     <a class="toc_title" href="#collections">
    190. 

  190.       Collections
    191. 

  191.     </a>
    192. 

  192.     <ul class="toc_section">
    193. 

  193.       <li>- <a href="#each">each</a></li>
    194. 

  194.       <li>- <a href="#map">map</a></li>
    195. 

  195.       <li>- <a href="#reduce">reduce</a></li>
    196. 

  196.       <li>- <a href="#reduceRight">reduceRight</a></li>
    197. 

  197.       <li>- <a href="#find">find</a></li>
    198. 

  198.       <li>- <a href="#filter">filter</a></li>
    199. 

  199.       <li>- <a href="#where">where</a></li>
    200. 

  200.       <li>- <a href="#reject">reject</a></li>
    201. 

  201.       <li>- <a href="#every">every</a></li>
    202. 

  202.       <li>- <a href="#some">some</a></li>
    203. 

  203.       <li>- <a href="#contains">contains</a></li>
    204. 

  204.       <li>- <a href="#invoke">invoke</a></li>
    205. 

  205.       <li>- <a href="#pluck">pluck</a></li>
    206. 

  206.       <li>- <a href="#max">max</a></li>
    207. 

  207.       <li>- <a href="#min">min</a></li>
    208. 

  208.       <li>- <a href="#sortBy">sortBy</a></li>
    209. 

  209.       <li>- <a href="#groupBy">groupBy</a></li>
    210. 

  210.       <li>- <a href="#countBy">countBy</a></li>
    211. 

  211.       <li>- <a href="#shuffle">shuffle</a></li>
    212. 

  212.       <li>- <a href="#toArray">toArray</a></li>
    213. 

  213.       <li>- <a href="#size">size</a></li>
    214. 

  214.     </ul>
    215. 

  215. 

  216.     <a class="toc_title" href="#arrays">
    217. 

  217.       Arrays
    218. 

  218.     </a>
    219. 

  219.     <ul class="toc_section">
    220. 

  220.       <li>- <a href="#first">first</a></li>
    221. 

  221.       <li>- <a href="#initial">initial</a></li>
    222. 

  222.       <li>- <a href="#last">last</a></li>
    223. 

  223.       <li>- <a href="#rest">rest</a></li>
    224. 

  224.       <li>- <a href="#compact">compact</a></li>
    225. 

  225.       <li>- <a href="#flatten">flatten</a></li>
    226. 

  226.       <li>- <a href="#without">without</a></li>
    227. 

  227.       <li>- <a href="#union">union</a></li>
    228. 

  228.       <li>- <a href="#intersection">intersection</a></li>
    229. 

  229.       <li>- <a href="#difference">difference</a></li>
    230. 

  230.       <li>- <a href="#uniq">uniq</a></li>
    231. 

  231.       <li>- <a href="#zip">zip</a></li>
    232. 

  232.       <li>- <a href="#object">object</a></li>
    233. 

  233.       <li>- <a href="#indexOf">indexOf</a></li>
    234. 

  234.       <li>- <a href="#lastIndexOf">lastIndexOf</a></li>
    235. 

  235.       <li>- <a href="#sortedIndex">sortedIndex</a></li>
    236. 

  236.       <li>- <a href="#range">range</a></li>
    237. 

  237.     </ul>
    238. 

  238. 

  239.     <a class="toc_title" href="#functions">
    240. 

  240.       Functions
    241. 

  241.     </a>
    242. 

  242.     <ul class="toc_section">
    243. 

  243.       <li>- <a href="#bind">bind</a></li>
    244. 

  244.       <li>- <a href="#bindAll">bindAll</a></li>
    245. 

  245.       <li>- <a href="#memoize">memoize</a></li>
    246. 

  246.       <li>- <a href="#delay">delay</a></li>
    247. 

  247.       <li>- <a href="#defer">defer</a></li>
    248. 

  248.       <li>- <a href="#throttle">throttle</a></li>
    249. 

  249.       <li>- <a href="#debounce">debounce</a></li>
    250. 

  250.       <li>- <a href="#once">once</a></li>
    251. 

  251.       <li>- <a href="#after">after</a></li>
    252. 

  252.       <li>- <a href="#wrap">wrap</a></li>
    253. 

  253.       <li>- <a href="#compose">compose</a></li>
    254. 

  254.     </ul>
    255. 

  255. 

  256.     <a class="toc_title" href="#objects">
    257. 

  257.       Objects
    258. 

  258.     </a>
    259. 

  259.     <ul class="toc_section">
    260. 

  260.       <li>- <a href="#keys">keys</a></li>
    261. 

  261.       <li>- <a href="#values">values</a></li>
    262. 

  262.       <li>- <a href="#pairs">pairs</a></li>
    263. 

  263.       <li>- <a href="#invert">invert</a></li>
    264. 

  264.       <li>- <a href="#object-functions">functions</a></li>
    265. 

  265.       <li>- <a href="#extend">extend</a></li>
    266. 

  266.       <li>- <a href="#pick">pick</a></li>
    267. 

  267.       <li>- <a href="#omit">omit</a></li>
    268. 

  268.       <li>- <a href="#defaults">defaults</a></li>
    269. 

  269.       <li>- <a href="#clone">clone</a></li>
    270. 

  270.       <li>- <a href="#tap">tap</a></li>
    271. 

  271.       <li>- <a href="#has">has</a></li>
    272. 

  272.       <li>- <a href="#isEqual">isEqual</a></li>
    273. 

  273.       <li>- <a href="#isEmpty">isEmpty</a></li>
    274. 

  274.       <li>- <a href="#isElement">isElement</a></li>
    275. 

  275.       <li>- <a href="#isArray">isArray</a></li>
    276. 

  276.       <li>- <a href="#isObject">isObject</a></li>
    277. 

  277.       <li>- <a href="#isArguments">isArguments</a></li>
    278. 

  278.       <li>- <a href="#isFunction">isFunction</a></li>
    279. 

  279.       <li>- <a href="#isString">isString</a></li>
    280. 

  280.       <li>- <a href="#isNumber">isNumber</a></li>
    281. 

  281.       <li>- <a href="#isFinite">isFinite</a></li>
    282. 

  282.       <li>- <a href="#isBoolean">isBoolean</a></li>
    283. 

  283.       <li>- <a href="#isDate">isDate</a></li>
    284. 

  284.       <li>- <a href="#isRegExp">isRegExp</a></li>
    285. 

  285.       <li>- <a href="#isNaN">isNaN</a></li>
    286. 

  286.       <li>- <a href="#isNull">isNull</a></li>
    287. 

  287.       <li>- <a href="#isUndefined">isUndefined</a></li>
    288. 

  288.     </ul>
    289. 

  289. 

  290.     <a class="toc_title" href="#utility">
    291. 

  291.       Utility
    292. 

  292.     </a>
    293. 

  293.     <ul class="toc_section">
    294. 

  294.       <li>- <a href="#noConflict">noConflict</a></li>
    295. 

  295.       <li>- <a href="#identity">identity</a></li>
    296. 

  296.       <li>- <a href="#times">times</a></li>
    297. 

  297.       <li>- <a href="#random">random</a></li>
    298. 

  298.       <li>- <a href="#mixin">mixin</a></li>
    299. 

  299.       <li>- <a href="#uniqueId">uniqueId</a></li>
    300. 

  300.       <li>- <a href="#escape">escape</a></li>
    301. 

  301.       <li>- <a href="#unescape">unescape</a></li>
    302. 

  302.       <li>- <a href="#result">result</a></li>
    303. 

  303.       <li>- <a href="#template">template</a></li>
    304. 

  304.     </ul>
    305. 

  305. 

  306.     <a class="toc_title" href="#chaining">
    307. 

  307.       Chaining
    308. 

  308.     </a>
    309. 

  309.     <ul class="toc_section">
    310. 

  310.       <li>- <a href="#chain">chain</a></li>
    311. 

  311.       <li>- <a href="#value">value</a></li>
    312. 

  312.     </ul>
    313. 

  313. 

  314.     <a class="toc_title" href="#links">
    315. 

  315.       Links
    316. 

  316.     </a>
    317. 

  317. 

  318.     <a class="toc_title" href="#changelog">
    319. 

  319.       Change Log
    320. 

  320.     </a>
    321. 

  321. 

  322.   </div>
    323. 

  323. 

  324.   <div class="container">
    325. 

  325. 

  326.     <p id="introduction">
    327. 

  327.       <img id="logo" src="docs/images/underscore.png" alt="Underscore.js" />
    328. 

  328.     </p>
    329. 

  329. 

  330.     <p>
    331. 

  331.       <a href="http://github.com/documentcloud/underscore/">Underscore</a> is a
    332. 

  332.       utility-belt library for JavaScript that provides a lot of the
    333. 

  333.       functional programming support that you would expect in
    334. 

  334.       <a href="http://prototypejs.org/api">Prototype.js</a>
    335. 

  335.       (or <a href="http://www.ruby-doc.org/core/classes/Enumerable.html">Ruby</a>),
    336. 

  336.       but without extending any of the built-in JavaScript objects. It's the
    337. 

  337.       tie to go along with <a href="http://docs.jquery.com">jQuery</a>'s tux,
    338. 

  338.       and <a href="http://backbonejs.org">Backbone.js</a>'s suspenders.
    339. 

  339.     </p>
    340. 

  340. 

  341.     <p>
    342. 

  342.       Underscore provides 80-odd functions that support both the usual
    343. 

  343.       functional suspects: <b>map</b>, <b>select</b>, <b>invoke</b> &mdash;
    344. 

  344.       as well as more specialized helpers: function binding, javascript
    345. 

  345.       templating, deep equality testing, and so on. It delegates to built-in
    346. 

  346.       functions, if present, so modern browsers will use the
    347. 

  347.       native implementations of <b>forEach</b>, <b>map</b>, <b>reduce</b>,
    348. 

  348.       <b>filter</b>, <b>every</b>, <b>some</b> and <b>indexOf</b>.
    349. 

  349.     </p>
    350. 

  350. 

  351.     <p>
    352. 

  352.       A complete <a href="test/">Test &amp; Benchmark Suite</a>
    353. 

  353.       is included for your perusal.
    354. 

  354.     </p>
    355. 

  355. 

  356.     <p>
    357. 

  357.       You may also read through the <a href="docs/underscore.html">annotated source code</a>.
    358. 

  358.     </p>
    359. 

  359. 

  360.     <p>
    361. 

  361.       The project is
    362. 

  362.       <a href="http://github.com/documentcloud/underscore/">hosted on GitHub</a>.
    363. 

  363.       You can report bugs and discuss features on the
    364. 

  364.       <a href="http://github.com/documentcloud/underscore/issues">issues page</a>,
    365. 

  365.       on Freenode in the <tt>#documentcloud</tt> channel,
    366. 

  366.       or send tweets to <a href="http://twitter.com/documentcloud">@documentcloud</a>.
    367. 

  367.     </p>
    368. 

  368. 

  369.     <p>
    370. 

  370.       <i>Underscore is an open-source component of <a href="http://documentcloud.org/">DocumentCloud</a>.</i>
    371. 

  371.     </p>
    372. 

  372. 

  373.     <h2>Downloads <i style="padding-left: 12px; font-size:12px;">(Right-click, and use "Save As")</i></h2>
    374. 

  374. 

  375.     <table>
    376. 

  376.       <tr>
    377. 

  377.         <td><a href="underscore.js">Development Version (1.4.2)</a></td>
    378. 

  378.         <td><i>40kb, Uncompressed with Plentiful Comments</i></td>
    379. 

  379.       </tr>
    380. 

  380.       <tr>
    381. 

  381.         <td><a href="underscore-min.js">Production Version (1.4.2)</a></td>
    382. 

  382.         <td><i>4kb, Minified and Gzipped</i></td>
    383. 

  383.       </tr>
    384. 

  384.       <tr>
    385. 

  385.         <td colspan="2"><div class="rule"></div></td>
    386. 

  386.       </tr>
    387. 

  387.       <tr>
    388. 

  388.         <td><a href="https://raw.github.com/documentcloud/underscore/master/underscore.js">Edge Version</a></td>
    389. 

  389.         <td><i>Unreleased, current <tt>master</tt>, use at your own risk</i></td>
    390. 

  390.       </tr>
    391. 

  391.     </table>
    392. 

  392. 

  393.     <div id="documentation">
    394. 

  394. 

  395.       <h2 id="collections">Collection Functions (Arrays or Objects)</h2>
    396. 

  396. 

  397.       <p id="each">
    398. 

  398.         <b class="header">each</b><code>_.each(list, iterator, [context])</code>
    399. 

  399.         <span class="alias">Alias: <b>forEach</b></span>
    400. 

  400.         <br />
    401. 

  401.         Iterates over a <b>list</b> of elements, yielding each in turn to an <b>iterator</b>
    402. 

  402.         function. The <b>iterator</b> is bound to the <b>context</b> object, if one is
    403. 

  403.         passed. Each invocation of <b>iterator</b> is called with three arguments:
    404. 

  404.         <tt>(element, index, list)</tt>. If <b>list</b> is a JavaScript object, <b>iterator</b>'s
    405. 

  405.         arguments will be <tt>(value, key, list)</tt>. Delegates to the native
    406. 

  406.         <b>forEach</b> function if it exists.
    407. 

  407.       </p>
    408. 

  408.       <pre>
    409. 

  409. _.each([1, 2, 3], function(num){ alert(num); });
    410. 

  410. =&gt; alerts each number in turn...
    411. 

  411. _.each({one : 1, two : 2, three : 3}, function(num, key){ alert(num); });
    412. 

  412. =&gt; alerts each number in turn...</pre>
    413. 

  413. 

  414.       <p id="map">
    415. 

  415.         <b class="header">map</b><code>_.map(list, iterator, [context])</code>
    416. 

  416.         <span class="alias">Alias: <b>collect</b></span>
    417. 

  417.         <br />
    418. 

  418.         Produces a new array of values by mapping each value in <b>list</b>
    419. 

  419.         through a transformation function (<b>iterator</b>). If the native <b>map</b> method
    420. 

  420.         exists, it will be used instead. If <b>list</b> is a JavaScript object,
    421. 

  421.         <b>iterator</b>'s arguments will be <tt>(value, key, list)</tt>.
    422. 

  422.       </p>
    423. 

  423.       <pre>
    424. 

  424. _.map([1, 2, 3], function(num){ return num * 3; });
    425. 

  425. =&gt; [3, 6, 9]
    426. 

  426. _.map({one : 1, two : 2, three : 3}, function(num, key){ return num * 3; });
    427. 

  427. =&gt; [3, 6, 9]</pre>
    428. 

  428. 

  429.       <p id="reduce">
    430. 

  430.         <b class="header">reduce</b><code>_.reduce(list, iterator, memo, [context])</code>
    431. 

  431.         <span class="alias">Aliases: <b>inject, foldl</b></span>
    432. 

  432.         <br />
    433. 

  433.         Also known as <b>inject</b> and <b>foldl</b>, <b>reduce</b> boils down a
    434. 

  434.         <b>list</b> of values into a single value. <b>Memo</b> is the initial state
    435. 

  435.         of the reduction, and each successive step of it should be returned by
    436. 

  436.         <b>iterator</b>. The iterator is passed four arguments: the <tt>memo</tt>,
    437. 

  437.         then the <tt>value</tt> and <tt>index</tt> (or key) of the iteration,
    438. 

  438.         and finally a reference to the entire <tt>list</tt>.
    439. 

  439.       </p>
    440. 

  440.       <pre>
    441. 

  441. var sum = _.reduce([1, 2, 3], function(memo, num){ return memo + num; }, 0);
    442. 

  442. =&gt; 6
    443. 

  443. </pre>
    444. 

  444. 

  445.       <p id="reduceRight">
    446. 

  446.         <b class="header">reduceRight</b><code>_.reduceRight(list, iterator, memo, [context])</code>
    447. 

  447.         <span class="alias">Alias: <b>foldr</b></span>
    448. 

  448.         <br />
    449. 

  449.         The right-associative version of <b>reduce</b>. Delegates to the
    450. 

  450.         JavaScript 1.8 version of <b>reduceRight</b>, if it exists. <b>Foldr</b>
    451. 

  451.         is not as useful in JavaScript as it would be in a language with lazy
    452. 

  452.         evaluation.
    453. 

  453.       </p>
    454. 

  454.       <pre>
    455. 

  455. var list = [[0, 1], [2, 3], [4, 5]];
    456. 

  456. var flat = _.reduceRight(list, function(a, b) { return a.concat(b); }, []);
    457. 

  457. =&gt; [4, 5, 2, 3, 0, 1]
    458. 

  458. </pre>
    459. 

  459. 

  460.       <p id="find">
    461. 

  461.         <b class="header">find</b><code>_.find(list, iterator, [context])</code>
    462. 

  462.         <span class="alias">Alias: <b>detect</b></span>
    463. 

  463.         <br />
    464. 

  464.         Looks through each value in the <b>list</b>, returning the first one that
    465. 

  465.         passes a truth test (<b>iterator</b>). The function returns as
    466. 

  466.         soon as it finds an acceptable element, and doesn't traverse the
    467. 

  467.         entire list.
    468. 

  468.       </p>
    469. 

  469.       <pre>
    470. 

  470. var even = _.find([1, 2, 3, 4, 5, 6], function(num){ return num % 2 == 0; });
    471. 

  471. =&gt; 2
    472. 

  472. </pre>
    473. 

  473. 

  474.       <p id="filter">
    475. 

  475.         <b class="header">filter</b><code>_.filter(list, iterator, [context])</code>
    476. 

  476.         <span class="alias">Alias: <b>select</b></span>
    477. 

  477.         <br />
    478. 

  478.         Looks through each value in the <b>list</b>, returning an array of all
    479. 

  479.         the values that pass a truth test (<b>iterator</b>). Delegates to the
    480. 

  480.         native <b>filter</b> method, if it exists.
    481. 

  481.       </p>
    482. 

  482.       <pre>
    483. 

  483. var evens = _.filter([1, 2, 3, 4, 5, 6], function(num){ return num % 2 == 0; });
    484. 

  484. =&gt; [2, 4, 6]
    485. 

  485. </pre>
    486. 

  486. 

  487.       <p id="where">
    488. 

  488.         <b class="header">where</b><code>_.where(list, properties)</code>
    489. 

  489.         <br />
    490. 

  490.         Looks through each value in the <b>list</b>, returning an array of all
    491. 

  491.         the values that contain all of the key-value pairs listed in <b>properties</b>.
    492. 

  492.       </p>
    493. 

  493.       <pre>
    494. 

  494. _.where(listOfPlays, {author: "Shakespeare", year: 1611});
    495. 

  495. =&gt; [{title: "Cymbeline", author: "Shakespeare", year: 1611},
    496. 

  496.     {title: "The Tempest", author: "Shakespeare", year: 1611}]
    497. 

  497. </pre>
    498. 

  498. 

  499.       <p id="reject">
    500. 

  500.         <b class="header">reject</b><code>_.reject(list, iterator, [context])</code>
    501. 

  501.         <br />
    502. 

  502.         Returns the values in <b>list</b> without the elements that the truth
    503. 

  503.         test (<b>iterator</b>) passes. The opposite of <b>filter</b>.
    504. 

  504.       </p>
    505. 

  505.       <pre>
    506. 

  506. var odds = _.reject([1, 2, 3, 4, 5, 6], function(num){ return num % 2 == 0; });
    507. 

  507. =&gt; [1, 3, 5]
    508. 

  508. </pre>
    509. 

  509. 

  510.       <p id="every">
    511. 

  511.         <b class="header">every</b><code>_.every(list, iterator, [context])</code>
    512. 

  512.         <span class="alias">Alias: <b>all</b></span>
    513. 

  513.         <br />
    514. 

  514.         Returns <i>true</i> if all of the values in the <b>list</b> pass the <b>iterator</b>
    515. 

  515.         truth test. Delegates to the native method <b>every</b>, if present.
    516. 

  516.       </p>
    517. 

  517.       <pre>
    518. 

  518. _.every([true, 1, null, 'yes'], _.identity);
    519. 

  519. =&gt; false
    520. 

  520. </pre>
    521. 

  521. 

  522.       <p id="some">
    523. 

  523.         <b class="header">some</b><code>_.some(list, [iterator], [context])</code>
    524. 

  524.         <span class="alias">Alias: <b>any</b></span>
    525. 

  525.         <br />
    526. 

  526.         Returns <i>true</i> if any of the values in the <b>list</b> pass the
    527. 

  527.         <b>iterator</b> truth test. Short-circuits and stops traversing the list
    528. 

  528.         if a true element is found. Delegates to the native method <b>some</b>,
    529. 

  529.         if present.
    530. 

  530.       </p>
    531. 

  531.       <pre>
    532. 

  532. _.some([null, 0, 'yes', false]);
    533. 

  533. =&gt; true
    534. 

  534. </pre>
    535. 

  535. 

  536.       <p id="contains">
    537. 

  537.         <b class="header">contains</b><code>_.contains(list, value)</code>
    538. 

  538.         <span class="alias">Alias: <b>include</b></span>
    539. 

  539.         <br />
    540. 

  540.         Returns <i>true</i> if the <b>value</b> is present in the <b>list</b>.
    541. 

  541.         Uses <b>indexOf</b> internally, if <b>list</b> is an Array.
    542. 

  542.       </p>
    543. 

  543.       <pre>
    544. 

  544. _.contains([1, 2, 3], 3);
    545. 

  545. =&gt; true
    546. 

  546. </pre>
    547. 

  547. 

  548.       <p id="invoke">
    549. 

  549.         <b class="header">invoke</b><code>_.invoke(list, methodName, [*arguments])</code>
    550. 

  550.         <br />
    551. 

  551.         Calls the method named by <b>methodName</b> on each value in the <b>list</b>.
    552. 

  552.         Any extra arguments passed to <b>invoke</b> will be forwarded on to the
    553. 

  553.         method invocation.
    554. 

  554.       </p>
    555. 

  555.       <pre>
    556. 

  556. _.invoke([[5, 1, 7], [3, 2, 1]], 'sort');
    557. 

  557. =&gt; [[1, 5, 7], [1, 2, 3]]
    558. 

  558. </pre>
    559. 

  559. 

  560.       <p id="pluck">
    561. 

  561.         <b class="header">pluck</b><code>_.pluck(list, propertyName)</code>
    562. 

  562.         <br />
    563. 

  563.         A convenient version of what is perhaps the most common use-case for
    564. 

  564.         <b>map</b>: extracting a list of property values.
    565. 

  565.       </p>
    566. 

  566.       <pre>
    567. 

  567. var stooges = [{name : 'moe', age : 40}, {name : 'larry', age : 50}, {name : 'curly', age : 60}];
    568. 

  568. _.pluck(stooges, 'name');
    569. 

  569. =&gt; ["moe", "larry", "curly"]
    570. 

  570. </pre>
    571. 

  571. 

  572.       <p id="max">
    573. 

  573.         <b class="header">max</b><code>_.max(list, [iterator], [context])</code>
    574. 

  574.         <br />
    575. 

  575.         Returns the maximum value in <b>list</b>. If <b>iterator</b> is passed,
    576. 

  576.         it will be used on each value to generate the criterion by which the
    577. 

  577.         value is ranked.
    578. 

  578.       </p>
    579. 

  579.       <pre>
    580. 

  580. var stooges = [{name : 'moe', age : 40}, {name : 'larry', age : 50}, {name : 'curly', age : 60}];
    581. 

  581. _.max(stooges, function(stooge){ return stooge.age; });
    582. 

  582. =&gt; {name : 'curly', age : 60};
    583. 

  583. </pre>
    584. 

  584. 

  585.       <p id="min">
    586. 

  586.         <b class="header">min</b><code>_.min(list, [iterator], [context])</code>
    587. 

  587.         <br />
    588. 

  588.         Returns the minimum value in <b>list</b>. If <b>iterator</b> is passed,
    589. 

  589.         it will be used on each value to generate the criterion by which the
    590. 

  590.         value is ranked.
    591. 

  591.       </p>
    592. 

  592.       <pre>
    593. 

  593. var numbers = [10, 5, 100, 2, 1000];
    594. 

  594. _.min(numbers);
    595. 

  595. =&gt; 2
    596. 

  596. </pre>
    597. 

  597. 

  598.       <p id="sortBy">
    599. 

  599.         <b class="header">sortBy</b><code>_.sortBy(list, iterator, [context])</code>
    600. 

  600.         <br />
    601. 

  601.         Returns a sorted copy of <b>list</b>, ranked in ascending order by the
    602. 

  602.         results of running each value through <b>iterator</b>. Iterator may
    603. 

  603.         also be the string name of the property to sort by (eg. <tt>length</tt>).
    604. 

  604.       </p>
    605. 

  605.       <pre>
    606. 

  606. _.sortBy([1, 2, 3, 4, 5, 6], function(num){ return Math.sin(num); });
    607. 

  607. =&gt; [5, 4, 6, 3, 1, 2]
    608. 

  608. </pre>
    609. 

  609. 

  610.       <p id="groupBy">
    611. 

  611.         <b class="header">groupBy</b><code>_.groupBy(list, iterator)</code>
    612. 

  612.         <br />
    613. 

  613.         Splits a collection into sets, grouped by the result of running each
    614. 

  614.         value through <b>iterator</b>. If <b>iterator</b> is a string instead of
    615. 

  615.         a function, groups by the property named by <b>iterator</b> on each of
    616. 

  616.         the values.
    617. 

  617.       </p>
    618. 

  618.       <pre>
    619. 

  619. _.groupBy([1.3, 2.1, 2.4], function(num){ return Math.floor(num); });
    620. 

  620. =&gt; {1: [1.3], 2: [2.1, 2.4]}
    621. 

  621. 

  622. _.groupBy(['one', 'two', 'three'], 'length');
    623. 

  623. =&gt; {3: ["one", "two"], 5: ["three"]}
    624. 

  624. </pre>
    625. 

  625. 

  626.       <p id="countBy">
    627. 

  627.         <b class="header">countBy</b><code>_.countBy(list, iterator)</code>
    628. 

  628.         <br />
    629. 

  629.         Sorts a list into groups and returns a count for the number of objects
    630. 

  630.         in each group.
    631. 

  631.         Similar to <tt>groupBy</tt>, but instead of returning a list of values,
    632. 

  632.         returns a count for the number of values in that group.
    633. 

  633.       </p>
    634. 

  634.       <pre>
    635. 

  635. _.countBy([1, 2, 3, 4, 5], function(num) {
    636. 

  636.   return num % 2 == 0 ? 'even' : 'odd';
    637. 

  637. });
    638. 

  638. =&gt; {odd: 3, even: 2}
    639. 

  639. </pre>
    640. 

  640. 

  641.       <p id="shuffle">
    642. 

  642.         <b class="header">shuffle</b><code>_.shuffle(list)</code>
    643. 

  643.         <br />
    644. 

  644.         Returns a shuffled copy of the <b>list</b>, using a version of the
    645. 

  645.         <a href="http://en.wikipedia.org/wiki/Fisher%E2%80%93Yates_shuffle">Fisher-Yates shuffle</a>.
    646. 

  646.       </p>
    647. 

  647.       <pre>
    648. 

  648. _.shuffle([1, 2, 3, 4, 5, 6]);
    649. 

  649. =&gt; [4, 1, 6, 3, 5, 2]
    650. 

  650. </pre>
    651. 

  651. 

  652.       <p id="toArray">
    653. 

  653.         <b class="header">toArray</b><code>_.toArray(list)</code>
    654. 

  654.         <br />
    655. 

  655.         Converts the <b>list</b> (anything that can be iterated over), into a
    656. 

  656.         real Array. Useful for transmuting the <b>arguments</b> object.
    657. 

  657.       </p>
    658. 

  658.       <pre>
    659. 

  659. (function(){ return _.toArray(arguments).slice(1); })(1, 2, 3, 4);
    660. 

  660. =&gt; [2, 3, 4]
    661. 

  661. </pre>
    662. 

  662. 

  663.       <p id="size">
    664. 

  664.         <b class="header">size</b><code>_.size(list)</code>
    665. 

  665.         <br />
    666. 

  666.         Return the number of values in the <b>list</b>.
    667. 

  667.       </p>
    668. 

  668.       <pre>
    669. 

  669. _.size({one : 1, two : 2, three : 3});
    670. 

  670. =&gt; 3
    671. 

  671. </pre>
    672. 

  672. 

  673.       <h2 id="arrays">Array Functions</h2>
    674. 

  674. 

  675.       <p>
    676. 

  676.         <i>
    677. 

  677.           Note: All array functions will also work on the <b>arguments</b> object.
    678. 

  678.           However, Underscore functions are not designed to work on "sparse" arrays.
    679. 

  679.         </i>
    680. 

  680.       </p>
    681. 

  681. 

  682.       <p id="first">
    683. 

  683.         <b class="header">first</b><code>_.first(array, [n])</code>
    684. 

  684.         <span class="alias">Alias: <b>head</b>, <b>take</b></span>
    685. 

  685.         <br />
    686. 

  686.         Returns the first element of an <b>array</b>. Passing <b>n</b> will
    687. 

  687.         return the first <b>n</b> elements of the array.
    688. 

  688.       </p>
    689. 

  689.       <pre>
    690. 

  690. _.first([5, 4, 3, 2, 1]);
    691. 

  691. =&gt; 5
    692. 

  692. </pre>
    693. 

  693. 

  694.       <p id="initial">
    695. 

  695.         <b class="header">initial</b><code>_.initial(array, [n])</code>
    696. 

  696.         <br />
    697. 

  697.         Returns everything but the last entry of the array. Especially useful on
    698. 

  698.         the arguments object. Pass <b>n</b> to exclude the last <b>n</b> elements
    699. 

  699.         from the result.
    700. 

  700.       </p>
    701. 

  701.       <pre>
    702. 

  702. _.initial([5, 4, 3, 2, 1]);
    703. 

  703. =&gt; [5, 4, 3, 2]
    704. 

  704. </pre>
    705. 

  705. 

  706.       <p id="last">
    707. 

  707.         <b class="header">last</b><code>_.last(array, [n])</code>
    708. 

  708.         <br />
    709. 

  709.         Returns the last element of an <b>array</b>. Passing <b>n</b> will return
    710. 

  710.         the last <b>n</b> elements of the array.
    711. 

  711.       </p>
    712. 

  712.       <pre>
    713. 

  713. _.last([5, 4, 3, 2, 1]);
    714. 

  714. =&gt; 1
    715. 

  715. </pre>
    716. 

  716. 

  717.       <p id="rest">
    718. 

  718.         <b class="header">rest</b><code>_.rest(array, [index])</code>
    719. 

  719.         <span class="alias">Alias: <b>tail, drop</b></span>
    720. 

  720.         <br />
    721. 

  721.         Returns the <b>rest</b> of the elements in an array. Pass an <b>index</b>
    722. 

  722.         to return the values of the array from that index onward.
    723. 

  723.       </p>
    724. 

  724.       <pre>
    725. 

  725. _.rest([5, 4, 3, 2, 1]);
    726. 

  726. =&gt; [4, 3, 2, 1]
    727. 

  727. </pre>
    728. 

  728. 

  729.       <p id="compact">
    730. 

  730.         <b class="header">compact</b><code>_.compact(array)</code>
    731. 

  731.         <br />
    732. 

  732.         Returns a copy of the <b>array</b> with all falsy values removed.
    733. 

  733.         In JavaScript, <i>false</i>, <i>null</i>, <i>0</i>, <i>""</i>,
    734. 

  734.         <i>undefined</i> and <i>NaN</i> are all falsy.
    735. 

  735.       </p>
    736. 

  736.       <pre>
    737. 

  737. _.compact([0, 1, false, 2, '', 3]);
    738. 

  738. =&gt; [1, 2, 3]
    739. 

  739. </pre>
    740. 

  740. 

  741.       <p id="flatten">
    742. 

  742.         <b class="header">flatten</b><code>_.flatten(array, [shallow])</code>
    743. 

  743.         <br />
    744. 

  744.         Flattens a nested <b>array</b> (the nesting can be to any depth). If you
    745. 

  745.         pass <b>shallow</b>, the array will only be flattened a single level.
    746. 

  746.       </p>
    747. 

  747.       <pre>
    748. 

  748. _.flatten([1, [2], [3, [[4]]]]);
    749. 

  749. =&gt; [1, 2, 3, 4];
    750. 

  750. 

  751. _.flatten([1, [2], [3, [[4]]]], true);
    752. 

  752. =&gt; [1, 2, 3, [[4]]];
    753. 

  753. </pre>
    754. 

  754. 

  755.       <p id="without">
    756. 

  756.         <b class="header">without</b><code>_.without(array, [*values])</code>
    757. 

  757.         <br />
    758. 

  758.         Returns a copy of the <b>array</b> with all instances of the <b>values</b>
    759. 

  759.         removed.
    760. 

  760.       </p>
    761. 

  761.       <pre>
    762. 

  762. _.without([1, 2, 1, 0, 3, 1, 4], 0, 1);
    763. 

  763. =&gt; [2, 3, 4]
    764. 

  764. </pre>
    765. 

  765. 

  766.       <p id="union">
    767. 

  767.         <b class="header">union</b><code>_.union(*arrays)</code>
    768. 

  768.         <br />
    769. 

  769.         Computes the union of the passed-in <b>arrays</b>: the list of unique items,
    770. 

  770.         in order, that are present in one or more of the <b>arrays</b>.
    771. 

  771.       </p>
    772. 

  772.       <pre>
    773. 

  773. _.union([1, 2, 3], [101, 2, 1, 10], [2, 1]);
    774. 

  774. =&gt; [1, 2, 3, 101, 10]
    775. 

  775. </pre>
    776. 

  776. 

  777.       <p id="intersection">
    778. 

  778.         <b class="header">intersection</b><code>_.intersection(*arrays)</code>
    779. 

  779.         <br />
    780. 

  780.         Computes the list of values that are the intersection of all the <b>arrays</b>.
    781. 

  781.         Each value in the result is present in each of the <b>arrays</b>.
    782. 

  782.       </p>
    783. 

  783.       <pre>
    784. 

  784. _.intersection([1, 2, 3], [101, 2, 1, 10], [2, 1]);
    785. 

  785. =&gt; [1, 2]
    786. 

  786. </pre>
    787. 

  787. 

  788.       <p id="difference">
    789. 

  789.         <b class="header">difference</b><code>_.difference(array, *others)</code>
    790. 

  790.         <br />
    791. 

  791.         Similar to <b>without</b>, but returns the values from <b>array</b> that
    792. 

  792.         are not present in the <b>other</b> arrays.
    793. 

  793.       </p>
    794. 

  794.       <pre>
    795. 

  795. _.difference([1, 2, 3, 4, 5], [5, 2, 10]);
    796. 

  796. =&gt; [1, 3, 4]
    797. 

  797. </pre>
    798. 

  798. 

  799.       <p id="uniq">
    800. 

  800.         <b class="header">uniq</b><code>_.uniq(array, [isSorted], [iterator])</code>
    801. 

  801.         <span class="alias">Alias: <b>unique</b></span>
    802. 

  802.         <br />
    803. 

  803.         Produces a duplicate-free version of the <b>array</b>, using <i>===</i> to test
    804. 

  804.         object equality. If you know in advance that the <b>array</b> is sorted,
    805. 

  805.         passing <i>true</i> for <b>isSorted</b> will run a much faster algorithm.
    806. 

  806.         If you want to compute unique items based on a transformation, pass an
    807. 

  807.         <b>iterator</b> function.
    808. 

  808.       </p>
    809. 

  809.       <pre>
    810. 

  810. _.uniq([1, 2, 1, 3, 1, 4]);
    811. 

  811. =&gt; [1, 2, 3, 4]
    812. 

  812. </pre>
    813. 

  813. 

  814.       <p id="zip">
    815. 

  815.         <b class="header">zip</b><code>_.zip(*arrays)</code>
    816. 

  816.         <br />
    817. 

  817.         Merges together the values of each of the <b>arrays</b> with the
    818. 

  818.         values at the corresponding position. Useful when you have separate
    819. 

  819.         data sources that are coordinated through matching array indexes.
    820. 

  820.         If you're working with a matrix of nested arrays, <b>zip.apply</b>
    821. 

  821.         can transpose the matrix in a similar fashion.
    822. 

  822.       </p>
    823. 

  823.       <pre>
    824. 

  824. _.zip(['moe', 'larry', 'curly'], [30, 40, 50], [true, false, false]);
    825. 

  825. =&gt; [["moe", 30, true], ["larry", 40, false], ["curly", 50, false]]
    826. 

  826. </pre>
    827. 

  827. 

  828.       <p id="object">
    829. 

  829.         <b class="header">object</b><code>_.object(list, [values])</code>
    830. 

  830.         <br />
    831. 

  831.         Converts arrays into objects. Pass either a single list of
    832. 

  832.         <tt>[key, value]</tt> pairs, or a list of keys, and a list of values.
    833. 

  833.       </p>
    834. 

  834.       <pre>
    835. 

  835. _.object(['moe', 'larry', 'curly'], [30, 40, 50]);
    836. 

  836. =&gt; {moe: 30, larry: 40, curly: 50}
    837. 

  837. 

  838. _.object([['moe', 30], ['larry', 40], ['curly', 50]]);
    839. 

  839. =&gt; {moe: 30, larry: 40, curly: 50}
    840. 

  840. </pre>
    841. 

  841. 

  842.       <p id="indexOf">
    843. 

  843.         <b class="header">indexOf</b><code>_.indexOf(array, value, [isSorted])</code>
    844. 

  844.         <br />
    845. 

  845.         Returns the index at which <b>value</b> can be found in the <b>array</b>,
    846. 

  846.         or <i>-1</i> if value is not present in the <b>array</b>. Uses the native
    847. 

  847.         <b>indexOf</b> function unless it's missing. If you're working with a
    848. 

  848.         large array, and you know that the array is already sorted, pass <tt>true</tt>
    849. 

  849.         for <b>isSorted</b> to use a faster binary search ... or, pass a number as
    850. 

  850.         the third argument in order to look for the first matching value in the
    851. 

  851.         array after the given index.
    852. 

  852.       </p>
    853. 

  853.       <pre>
    854. 

  854. _.indexOf([1, 2, 3], 2);
    855. 

  855. =&gt; 1
    856. 

  856. </pre>
    857. 

  857. 

  858.       <p id="lastIndexOf">
    859. 

  859.         <b class="header">lastIndexOf</b><code>_.lastIndexOf(array, value, [fromIndex])</code>
    860. 

  860.         <br />
    861. 

  861.         Returns the index of the last occurrence of <b>value</b> in the <b>array</b>,
    862. 

  862.         or <i>-1</i> if value is not present. Uses the native <b>lastIndexOf</b>
    863. 

  863.         function if possible. Pass <b>fromIndex</b> to start your search at a
    864. 

  864.         given index.
    865. 

  865.       </p>
    866. 

  866.       <pre>
    867. 

  867. _.lastIndexOf([1, 2, 3, 1, 2, 3], 2);
    868. 

  868. =&gt; 4
    869. 

  869. </pre>
    870. 

  870. 

  871.       <p id="sortedIndex">
    872. 

  872.         <b class="header">sortedIndex</b><code>_.sortedIndex(list, value, [iterator])</code>
    873. 

  873.         <br />
    874. 

  874.         Uses a binary search to determine the index at which the <b>value</b>
    875. 

  875.         <i>should</i> be inserted into the <b>list</b> in order to maintain the <b>list</b>'s
    876. 

  876.         sorted order. If an <b>iterator</b> is passed, it will be used to compute
    877. 

  877.         the sort ranking of each value, including the <b>value</b> you pass.
    878. 

  878.       </p>
    879. 

  879.       <pre>
    880. 

  880. _.sortedIndex([10, 20, 30, 40, 50], 35);
    881. 

  881. =&gt; 3
    882. 

  882. </pre>
    883. 

  883. 

  884.       <p id="range">
    885. 

  885.         <b class="header">range</b><code>_.range([start], stop, [step])</code>
    886. 

  886.         <br />
    887. 

  887.         A function to create flexibly-numbered lists of integers, handy for
    888. 

  888.         <tt>each</tt> and <tt>map</tt> loops. <b>start</b>, if omitted, defaults
    889. 

  889.         to <i>0</i>; <b>step</b> defaults to <i>1</i>. Returns a list of integers
    890. 

  890.         from <b>start</b> to <b>stop</b>, incremented (or decremented) by <b>step</b>,
    891. 

  891.         exclusive.
    892. 

  892.       </p>
    893. 

  893.       <pre>
    894. 

  894. _.range(10);
    895. 

  895. =&gt; [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
    896. 

  896. _.range(1, 11);
    897. 

  897. =&gt; [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
    898. 

  898. _.range(0, 30, 5);
    899. 

  899. =&gt; [0, 5, 10, 15, 20, 25]
    900. 

  900. _.range(0, -10, -1);
    901. 

  901. =&gt; [0, -1, -2, -3, -4, -5, -6, -7, -8, -9]
    902. 

  902. _.range(0);
    903. 

  903. =&gt; []
    904. 

  904. </pre>
    905. 

  905. 

  906.       <h2 id="functions">Function (uh, ahem) Functions</h2>
    907. 

  907. 

  908.       <p id="bind">
    909. 

  909.         <b class="header">bind</b><code>_.bind(function, object, [*arguments])</code>
    910. 

  910.         <br />
    911. 

  911.         Bind a <b>function</b> to an <b>object</b>, meaning that whenever
    912. 

  912.         the function is called, the value of <i>this</i> will be the <b>object</b>.
    913. 

  913.         Optionally, bind <b>arguments</b> to the <b>function</b> to pre-fill them,
    914. 

  914.         also known as <b>partial application</b>.
    915. 

  915.       </p>
    916. 

  916.       <pre>
    917. 

  917. var func = function(greeting){ return greeting + ': ' + this.name };
    918. 

  918. func = _.bind(func, {name : 'moe'}, 'hi');
    919. 

  919. func();
    920. 

  920. =&gt; 'hi: moe'
    921. 

  921. </pre>
    922. 

  922. 

  923.       <p id="bindAll">
    924. 

  924.         <b class="header">bindAll</b><code>_.bindAll(object, [*methodNames])</code>
    925. 

  925.         <br />
    926. 

  926.         Binds a number of methods on the <b>object</b>, specified by
    927. 

  927.         <b>methodNames</b>, to be run in the context of that object whenever they
    928. 

  928.         are invoked. Very handy for binding functions that are going to be used
    929. 

  929.         as event handlers, which would otherwise be invoked with a fairly useless
    930. 

  930.         <i>this</i>. If no <b>methodNames</b> are provided, all of the object's
    931. 

  931.         function properties will be bound to it.
    932. 

  932.       </p>
    933. 

  933.       <pre>
    934. 

  934. var buttonView = {
    935. 

  935.   label   : 'underscore',
    936. 

  936.   onClick : function(){ alert('clicked: ' + this.label); },
    937. 

  937.   onHover : function(){ console.log('hovering: ' + this.label); }
    938. 

  938. };
    939. 

  939. _.bindAll(buttonView);
    940. 

  940. jQuery('#underscore_button').bind('click', buttonView.onClick);
    941. 

  941. =&gt; When the button is clicked, this.label will have the correct value...
    942. 

  942. </pre>
    943. 

  943. 

  944.       <p id="memoize">
    945. 

  945.         <b class="header">memoize</b><code>_.memoize(function, [hashFunction])</code>
    946. 

  946.         <br />
    947. 

  947.         Memoizes a given <b>function</b> by caching the computed result. Useful
    948. 

  948.         for speeding up slow-running computations. If passed an optional
    949. 

  949.         <b>hashFunction</b>, it will be used to compute the hash key for storing
    950. 

  950.         the result, based on the arguments to the original function. The default
    951. 

  951.         <b>hashFunction</b> just uses the first argument to the memoized function
    952. 

  952.         as the key.
    953. 

  953.       </p>
    954. 

  954.       <pre>
    955. 

  955. var fibonacci = _.memoize(function(n) {
    956. 

  956.   return n &lt; 2 ? n : fibonacci(n - 1) + fibonacci(n - 2);
    957. 

  957. });
    958. 

  958. </pre>
    959. 

  959. 

  960.       <p id="delay">
    961. 

  961.         <b class="header">delay</b><code>_.delay(function, wait, [*arguments])</code>
    962. 

  962.         <br />
    963. 

  963.         Much like <b>setTimeout</b>, invokes <b>function</b> after <b>wait</b>
    964. 

  964.         milliseconds. If you pass the optional <b>arguments</b>, they will be
    965. 

  965.         forwarded on to the <b>function</b> when it is invoked.
    966. 

  966.       </p>
    967. 

  967.       <pre>
    968. 

  968. var log = _.bind(console.log, console);
    969. 

  969. _.delay(log, 1000, 'logged later');
    970. 

  970. =&gt; 'logged later' // Appears after one second.
    971. 

  971. </pre>
    972. 

  972. 

  973.       <p id="defer">
    974. 

  974.         <b class="header">defer</b><code>_.defer(function, [*arguments])</code>
    975. 

  975.         <br />
    976. 

  976.         Defers invoking the <b>function</b> until the current call stack has cleared,
    977. 

  977.         similar to using <b>setTimeout</b> with a delay of 0. Useful for performing
    978. 

  978.         expensive computations or HTML rendering in chunks without blocking the UI thread
    979. 

  979.         from updating. If you pass the optional <b>arguments</b>, they will be
    980. 

  980.         forwarded on to the <b>function</b> when it is invoked.
    981. 

  981.       </p>
    982. 

  982.       <pre>
    983. 

  983. _.defer(function(){ alert('deferred'); });
    984. 

  984. // Returns from the function before the alert runs.
    985. 

  985. </pre>
    986. 

  986. 

  987.       <p id="throttle">
    988. 

  988.         <b class="header">throttle</b><code>_.throttle(function, wait)</code>
    989. 

  989.         <br />
    990. 

  990.         Creates and returns a new, throttled version of the passed function,
    991. 

  991.         that, when invoked repeatedly, will only actually call the original function
    992. 

  992.         at most once per every <b>wait</b>
    993. 

  993.         milliseconds. Useful for rate-limiting events that occur faster than you
    994. 

  994.         can keep up with.
    995. 

  995.       </p>
    996. 

  996.       <pre>
    997. 

  997. var throttled = _.throttle(updatePosition, 100);
    998. 

  998. $(window).scroll(throttled);
    999. 

  999. </pre>
    1000. 

  1000. 

  1001.       <p id="debounce">
    1002. 

  1002.         <b class="header">debounce</b><code>_.debounce(function, wait, [immediate])</code>
    1003. 

  1003.         <br />
    1004. 

  1004.         Creates and returns a new debounced version of the passed function that
    1005. 

  1005.         will postpone its execution until after
    1006. 

  1006.         <b>wait</b> milliseconds have elapsed since the last time it
    1007. 

  1007.         was invoked. Useful for implementing behavior that should only happen
    1008. 

  1008.         <i>after</i> the input has stopped arriving. For example: rendering a
    1009. 

  1009.         preview of a Markdown comment, recalculating a layout after the window
    1010. 

  1010.         has stopped being resized, and so on.
    1011. 

  1011.       </p>
    1012. 

  1012. 

  1013.       <p>
    1014. 

  1014.         Pass <tt>true</tt> for the <b>immediate</b> parameter to cause
    1015. 

  1015.         <b>debounce</b> to trigger the function on the leading instead of the
    1016. 

  1016.         trailing edge of the <b>wait</b> interval. Useful in circumstances like
    1017. 

  1017.         preventing accidental double-clicks on a "submit" button from firing a
    1018. 

  1018.         second time.
    1019. 

  1019.       </p>
    1020. 

  1020. 

  1021.       <pre>
    1022. 

  1022. var lazyLayout = _.debounce(calculateLayout, 300);
    1023. 

  1023. $(window).resize(lazyLayout);
    1024. 

  1024. </pre>
    1025. 

  1025. 

  1026.       <p id="once">
    1027. 

  1027.         <b class="header">once</b><code>_.once(function)</code>
    1028. 

  1028.         <br />
    1029. 

  1029.         Creates a version of the function that can only be called one time.
    1030. 

  1030.         Repeated calls to the modified function will have no effect, returning
    1031. 

  1031.         the value from the original call. Useful for initialization functions,
    1032. 

  1032.         instead of having to set a boolean flag and then check it later.
    1033. 

  1033.       </p>
    1034. 

  1034.       <pre>
    1035. 

  1035. var initialize = _.once(createApplication);
    1036. 

  1036. initialize();
    1037. 

  1037. initialize();
    1038. 

  1038. // Application is only created once.
    1039. 

  1039. </pre>
    1040. 

  1040. 

  1041.       <p id="after">
    1042. 

  1042.         <b class="header">after</b><code>_.after(count, function)</code>
    1043. 

  1043.         <br />
    1044. 

  1044.         Creates a version of the function that will only be run after first
    1045. 

  1045.         being called <b>count</b> times. Useful for grouping asynchronous responses,
    1046. 

  1046.         where you want to be sure that all the async calls have finished, before
    1047. 

  1047.         proceeding.
    1048. 

  1048.       </p>
    1049. 

  1049.       <pre>
    1050. 

  1050. var renderNotes = _.after(notes.length, render);
    1051. 

  1051. _.each(notes, function(note) {
    1052. 

  1052.   note.asyncSave({success: renderNotes});
    1053. 

  1053. });
    1054. 

  1054. // renderNotes is run once, after all notes have saved.
    1055. 

  1055. </pre>
    1056. 

  1056. 

  1057.       <p id="wrap">
    1058. 

  1058.         <b class="header">wrap</b><code>_.wrap(function, wrapper)</code>
    1059. 

  1059.         <br />
    1060. 

  1060.         Wraps the first <b>function</b> inside of the <b>wrapper</b> function,
    1061. 

  1061.         passing it as the first argument. This allows the <b>wrapper</b> to
    1062. 

  1062.         execute code before and after the <b>function</b> runs, adjust the arguments,
    1063. 

  1063.         and execute it conditionally.
    1064. 

  1064.       </p>
    1065. 

  1065.       <pre>
    1066. 

  1066. var hello = function(name) { return "hello: " + name; };
    1067. 

  1067. hello = _.wrap(hello, function(func) {
    1068. 

  1068.   return "before, " + func("moe") + ", after";
    1069. 

  1069. });
    1070. 

  1070. hello();
    1071. 

  1071. =&gt; 'before, hello: moe, after'
    1072. 

  1072. </pre>
    1073. 

  1073. 

  1074.       <p id="compose">
    1075. 

  1075.         <b class="header">compose</b><code>_.compose(*functions)</code>
    1076. 

  1076.         <br />
    1077. 

  1077.         Returns the composition of a list of <b>functions</b>, where each function
    1078. 

  1078.         consumes the return value of the function that follows. In math terms,
    1079. 

  1079.         composing the functions <i>f()</i>, <i>g()</i>, and <i>h()</i> produces
    1080. 

  1080.         <i>f(g(h()))</i>.
    1081. 

  1081.       </p>
    1082. 

  1082.       <pre>
    1083. 

  1083. var greet    = function(name){ return "hi: " + name; };
    1084. 

  1084. var exclaim  = function(statement){ return statement + "!"; };
    1085. 

  1085. var welcome = _.compose(exclaim, greet);
    1086. 

  1086. welcome('moe');
    1087. 

  1087. =&gt; 'hi: moe!'
    1088. 

  1088. </pre>
    1089. 

  1089. 

  1090.       <h2 id="objects">Object Functions</h2>
    1091. 

  1091. 

  1092.       <p id="keys">
    1093. 

  1093.         <b class="header">keys</b><code>_.keys(object)</code>
    1094. 

  1094.         <br />
    1095. 

  1095.         Retrieve all the names of the <b>object</b>'s properties.
    1096. 

  1096.       </p>
    1097. 

  1097.       <pre>
    1098. 

  1098. _.keys({one : 1, two : 2, three : 3});
    1099. 

  1099. =&gt; ["one", "two", "three"]
    1100. 

  1100. </pre>
    1101. 

  1101. 

  1102.       <p id="values">
    1103. 

  1103.         <b class="header">values</b><code>_.values(object)</code>
    1104. 

  1104.         <br />
    1105. 

  1105.         Return all of the values of the <b>object</b>'s properties.
    1106. 

  1106.       </p>
    1107. 

  1107.       <pre>
    1108. 

  1108. _.values({one : 1, two : 2, three : 3});
    1109. 

  1109. =&gt; [1, 2, 3]
    1110. 

  1110. </pre>
    1111. 

  1111. 

  1112.       <p id="pairs">
    1113. 

  1113.         <b class="header">pairs</b><code>_.pairs(object)</code>
    1114. 

  1114.         <br />
    1115. 

  1115.         Convert an object into a list of <tt>[key, value]</tt> pairs.
    1116. 

  1116.       </p>
    1117. 

  1117.       <pre>
    1118. 

  1118. _.pairs({one: 1, two: 2, three: 3});
    1119. 

  1119. =&gt; [["one", 1], ["two", 2], ["three", 3]]
    1120. 

  1120. </pre>
    1121. 

  1121. 

  1122.       <p id="invert">
    1123. 

  1123.         <b class="header">invert</b><code>_.invert(object)</code>
    1124. 

  1124.         <br />
    1125. 

  1125.         Returns a copy of the <b>object</b> where the keys have become the values
    1126. 

  1126.         and the values the keys. For this to work, all of your object's values
    1127. 

  1127.         should be unique and string serializable.
    1128. 

  1128.       </p>
    1129. 

  1129.       <pre>
    1130. 

  1130. _.invert({Moe: "Moses", Larry: "Louis", Curly: "Jerome"});
    1131. 

  1131. =&gt; {Moses: "Moe", Louis: "Larry", Jerome: "Curly"};
    1132. 

  1132. </pre>
    1133. 

  1133. 

  1134.       <p id="object-functions">
    1135. 

  1135.         <b class="header">functions</b><code>_.functions(object)</code>
    1136. 

  1136.         <span class="alias">Alias: <b>methods</b></span>
    1137. 

  1137.         <br />
    1138. 

  1138.         Returns a sorted list of the names of every method in an object &mdash;
    1139. 

  1139.         that is to say, the name of every function property of the object.
    1140. 

  1140.       </p>
    1141. 

  1141.       <pre>
    1142. 

  1142. _.functions(_);
    1143. 

  1143. =&gt; ["all", "any", "bind", "bindAll", "clone", "compact", "compose" ...
    1144. 

  1144. </pre>
    1145. 

  1145. 

  1146.       <p id="extend">
    1147. 

  1147.         <b class="header">extend</b><code>_.extend(destination, *sources)</code>
    1148. 

  1148.         <br />
    1149. 

  1149.         Copy all of the properties in the <b>source</b> objects over to the
    1150. 

  1150.         <b>destination</b> object, and return the <b>destination</b> object.
    1151. 

  1151.         It's in-order, so the last source will override properties of the same
    1152. 

  1152.         name in previous arguments.
    1153. 

  1153.       </p>
    1154. 

  1154.       <pre>
    1155. 

  1155. _.extend({name : 'moe'}, {age : 50});
    1156. 

  1156. =&gt; {name : 'moe', age : 50}
    1157. 

  1157. </pre>
    1158. 

  1158. 

  1159.       <p id="pick">
    1160. 

  1160.         <b class="header">pick</b><code>_.pick(object, *keys)</code>
    1161. 

  1161.         <br />
    1162. 

  1162.         Return a copy of the <b>object</b>, filtered to only have values for
    1163. 

  1163.         the whitelisted <b>keys</b> (or array of valid keys).
    1164. 

  1164.       </p>
    1165. 

  1165.       <pre>
    1166. 

  1166. _.pick({name : 'moe', age: 50, userid : 'moe1'}, 'name', 'age');
    1167. 

  1167. =&gt; {name : 'moe', age : 50}
    1168. 

  1168. </pre>
    1169. 

  1169. 

  1170.       <p id="omit">
    1171. 

  1171.         <b class="header">omit</b><code>_.omit(object, *keys)</code>
    1172. 

  1172.         <br />
    1173. 

  1173.         Return a copy of the <b>object</b>, filtered to omit the blacklisted
    1174. 

  1174.         <b>keys</b> (or array of keys).
    1175. 

  1175.       </p>
    1176. 

  1176.       <pre>
    1177. 

  1177. _.omit({name : 'moe', age : 50, userid : 'moe1'}, 'userid');
    1178. 

  1178. =&gt; {name : 'moe', age : 50}
    1179. 

  1179. </pre>
    1180. 

  1180. 

  1181.       <p id="defaults">
    1182. 

  1182.         <b class="header">defaults</b><code>_.defaults(object, *defaults)</code>
    1183. 

  1183.         <br />
    1184. 

  1184.         Fill in null and undefined properties in <b>object</b> with values from the
    1185. 

  1185.         <b>defaults</b> objects, and return the <b>object</b>. As soon as the
    1186. 

  1186.         property is filled, further defaults will have no effect.
    1187. 

  1187.       </p>
    1188. 

  1188.       <pre>
    1189. 

  1189. var iceCream = {flavor : "chocolate"};
    1190. 

  1190. _.defaults(iceCream, {flavor : "vanilla", sprinkles : "lots"});
    1191. 

  1191. =&gt; {flavor : "chocolate", sprinkles : "lots"}
    1192. 

  1192. </pre>
    1193. 

  1193. 

  1194.       <p id="clone">
    1195. 

  1195.         <b class="header">clone</b><code>_.clone(object)</code>
    1196. 

  1196.         <br />
    1197. 

  1197.         Create a shallow-copied clone of the <b>object</b>. Any nested objects
    1198. 

  1198.         or arrays will be copied by reference, not duplicated.
    1199. 

  1199.       </p>
    1200. 

  1200.       <pre>
    1201. 

  1201. _.clone({name : 'moe'});
    1202. 

  1202. =&gt; {name : 'moe'};
    1203. 

  1203. </pre>
    1204. 

  1204. 

  1205.       <p id="tap">
    1206. 

  1206.         <b class="header">tap</b><code>_.tap(object, interceptor)</code>
    1207. 

  1207.         <br />
    1208. 

  1208.         Invokes <b>interceptor</b> with the <b>object</b>, and then returns <b>object</b>.
    1209. 

  1209.         The primary purpose of this method is to "tap into" a method chain, in order to perform operations on intermediate results within the chain.
    1210. 

  1210.       </p>
    1211. 

  1211.       <pre>
    1212. 

  1212. _.chain([1,2,3,200])
    1213. 

  1213.   .filter(function(num) { return num % 2 == 0; })
    1214. 

  1214.   .tap(alert)
    1215. 

  1215.   .map(function(num) { return num * num })
    1216. 

  1216.   .value();
    1217. 

  1217. =&gt; // [2, 200] (alerted)
    1218. 

  1218. =&gt; [4, 40000]
    1219. 

  1219. </pre>
    1220. 

  1220. 

  1221.       <p id="has">
    1222. 

  1222.         <b class="header">has</b><code>_.has(object, key)</code>
    1223. 

  1223.         <br />
    1224. 

  1224.         Does the object contain the given key? Identical to
    1225. 

  1225.         <tt>object.hasOwnProperty(key)</tt>, but uses a safe reference to the
    1226. 

  1226.         <tt>hasOwnProperty</tt> function, in case it's been
    1227. 

  1227.         <a href="http://www.devthought.com/2012/01/18/an-object-is-not-a-hash/">overridden accidentally</a>.
    1228. 

  1228.       </p>
    1229. 

  1229.       <pre>
    1230. 

  1230. _.has({a: 1, b: 2, c: 3}, "b");
    1231. 

  1231. =&gt; true
    1232. 

  1232. </pre>
    1233. 

  1233. 

  1234.       <p id="isEqual">
    1235. 

  1235.         <b class="header">isEqual</b><code>_.isEqual(object, other)</code>
    1236. 

  1236.         <br />
    1237. 

  1237.         Performs an optimized deep comparison between the two objects, to determine
    1238. 

  1238.         if they should be considered equal.
    1239. 

  1239.       </p>
    1240. 

  1240.       <pre>
    1241. 

  1241. var moe   = {name : 'moe', luckyNumbers : [13, 27, 34]};
    1242. 

  1242. var clone = {name : 'moe', luckyNumbers : [13, 27, 34]};
    1243. 

  1243. moe == clone;
    1244. 

  1244. =&gt; false
    1245. 

  1245. _.isEqual(moe, clone);
    1246. 

  1246. =&gt; true
    1247. 

  1247. </pre>
    1248. 

  1248. 

  1249.       <p id="isEmpty">
    1250. 

  1250.         <b class="header">isEmpty</b><code>_.isEmpty(object)</code>
    1251. 

  1251.         <br />
    1252. 

  1252.         Returns <i>true</i> if <b>object</b> contains no values.
    1253. 

  1253.       </p>
    1254. 

  1254.       <pre>
    1255. 

  1255. _.isEmpty([1, 2, 3]);
    1256. 

  1256. =&gt; false
    1257. 

  1257. _.isEmpty({});
    1258. 

  1258. =&gt; true
    1259. 

  1259. </pre>
    1260. 

  1260. 

  1261.       <p id="isElement">
    1262. 

  1262.         <b class="header">isElement</b><code>_.isElement(object)</code>
    1263. 

  1263.         <br />
    1264. 

  1264.         Returns <i>true</i> if <b>object</b> is a DOM element.
    1265. 

  1265.       </p>
    1266. 

  1266.       <pre>
    1267. 

  1267. _.isElement(jQuery('body')[0]);
    1268. 

  1268. =&gt; true
    1269. 

  1269. </pre>
    1270. 

  1270. 

  1271.       <p id="isArray">
    1272. 

  1272.         <b class="header">isArray</b><code>_.isArray(object)</code>
    1273. 

  1273.         <br />
    1274. 

  1274.         Returns <i>true</i> if <b>object</b> is an Array.
    1275. 

  1275.       </p>
    1276. 

  1276.       <pre>
    1277. 

  1277. (function(){ return _.isArray(arguments); })();
    1278. 

  1278. =&gt; false
    1279. 

  1279. _.isArray([1,2,3]);
    1280. 

  1280. =&gt; true
    1281. 

  1281. </pre>
    1282. 

  1282. 

  1283.       <p id="isObject">
    1284. 

  1284.         <b class="header">isObject</b><code>_.isObject(value)</code>
    1285. 

  1285.         <br />
    1286. 

  1286.         Returns <i>true</i> if <b>value</b> is an Object. Note that JavaScript
    1287. 

  1287.         arrays and functions are objects, while (normal) strings and numbers are not.
    1288. 

  1288.       </p>
    1289. 

  1289.       <pre>
    1290. 

  1290. _.isObject({});
    1291. 

  1291. =&gt; true
    1292. 

  1292. _.isObject(1);
    1293. 

  1293. =&gt; false
    1294. 

  1294. </pre>
    1295. 

  1295. 

  1296.       <p id="isArguments">
    1297. 

  1297.         <b class="header">isArguments</b><code>_.isArguments(object)</code>
    1298. 

  1298.         <br />
    1299. 

  1299.         Returns <i>true</i> if <b>object</b> is an Arguments object.
    1300. 

  1300.       </p>
    1301. 

  1301.       <pre>
    1302. 

  1302. (function(){ return _.isArguments(arguments); })(1, 2, 3);
    1303. 

  1303. =&gt; true
    1304. 

  1304. _.isArguments([1,2,3]);
    1305. 

  1305. =&gt; false
    1306. 

  1306. </pre>
    1307. 

  1307. 

  1308.       <p id="isFunction">
    1309. 

  1309.         <b class="header">isFunction</b><code>_.isFunction(object)</code>
    1310. 

  1310.         <br />
    1311. 

  1311.         Returns <i>true</i> if <b>object</b> is a Function.
    1312. 

  1312.       </p>
    1313. 

  1313.       <pre>
    1314. 

  1314. _.isFunction(alert);
    1315. 

  1315. =&gt; true
    1316. 

  1316. </pre>
    1317. 

  1317. 

  1318.       <p id="isString">
    1319. 

  1319.         <b class="header">isString</b><code>_.isString(object)</code>
    1320. 

  1320.         <br />
    1321. 

  1321.         Returns <i>true</i> if <b>object</b> is a String.
    1322. 

  1322.       </p>
    1323. 

  1323.       <pre>
    1324. 

  1324. _.isString("moe");
    1325. 

  1325. =&gt; true
    1326. 

  1326. </pre>
    1327. 

  1327. 

  1328.       <p id="isNumber">
    1329. 

  1329.         <b class="header">isNumber</b><code>_.isNumber(object)</code>
    1330. 

  1330.         <br />
    1331. 

  1331.         Returns <i>true</i> if <b>object</b> is a Number (including <tt>NaN</tt>).
    1332. 

  1332.       </p>
    1333. 

  1333.       <pre>
    1334. 

  1334. _.isNumber(8.4 * 5);
    1335. 

  1335. =&gt; true
    1336. 

  1336. </pre>
    1337. 

  1337. 

  1338.       <p id="isFinite">
    1339. 

  1339.         <b class="header">isFinite</b><code>_.isFinite(object)</code>
    1340. 

  1340.         <br />
    1341. 

  1341.         Returns <i>true</i> if <b>object</b> is a finite Number.
    1342. 

  1342.       </p>
    1343. 

  1343.       <pre>
    1344. 

  1344. _.isFinite(-101);
    1345. 

  1345. =&gt; true
    1346. 

  1346. 

  1347. _.isFinite(-Infinity);
    1348. 

  1348. =&gt; false
    1349. 

  1349. </pre>
    1350. 

  1350. 

  1351.       <p id="isBoolean">
    1352. 

  1352.         <b class="header">isBoolean</b><code>_.isBoolean(object)</code>
    1353. 

  1353.         <br />
    1354. 

  1354.         Returns <i>true</i> if <b>object</b> is either <i>true</i> or <i>false</i>.
    1355. 

  1355.       </p>
    1356. 

  1356.       <pre>
    1357. 

  1357. _.isBoolean(null);
    1358. 

  1358. =&gt; false
    1359. 

  1359. </pre>
    1360. 

  1360. 

  1361.       <p id="isDate">
    1362. 

  1362.         <b class="header">isDate</b><code>_.isDate(object)</code>
    1363. 

  1363.         <br />
    1364. 

  1364.         Returns <i>true</i> if <b>object</b> is a Date.
    1365. 

  1365.       </p>
    1366. 

  1366.       <pre>
    1367. 

  1367. _.isDate(new Date());
    1368. 

  1368. =&gt; true
    1369. 

  1369. </pre>
    1370. 

  1370. 

  1371.       <p id="isRegExp">
    1372. 

  1372.         <b class="header">isRegExp</b><code>_.isRegExp(object)</code>
    1373. 

  1373.         <br />
    1374. 

  1374.         Returns <i>true</i> if <b>object</b> is a RegExp.
    1375. 

  1375.       </p>
    1376. 

  1376.       <pre>
    1377. 

  1377. _.isRegExp(/moe/);
    1378. 

  1378. =&gt; true
    1379. 

  1379. </pre>
    1380. 

  1380. 

  1381.       <p id="isNaN">
    1382. 

  1382.         <b class="header">isNaN</b><code>_.isNaN(object)</code>
    1383. 

  1383.         <br />
    1384. 

  1384.         Returns <i>true</i> if <b>object</b> is <i>NaN</i>.<br /> Note: this is not
    1385. 

  1385.         the same as the native <b>isNaN</b> function, which will also return
    1386. 

  1386.         true if the variable is <i>undefined</i>.
    1387. 

  1387.       </p>
    1388. 

  1388.       <pre>
    1389. 

  1389. _.isNaN(NaN);
    1390. 

  1390. =&gt; true
    1391. 

  1391. isNaN(undefined);
    1392. 

  1392. =&gt; true
    1393. 

  1393. _.isNaN(undefined);
    1394. 

  1394. =&gt; false
    1395. 

  1395. </pre>
    1396. 

  1396. 

  1397.       <p id="isNull">
    1398. 

  1398.         <b class="header">isNull</b><code>_.isNull(object)</code>
    1399. 

  1399.         <br />
    1400. 

  1400.         Returns <i>true</i> if the value of <b>object</b> is <i>null</i>.
    1401. 

  1401.       </p>
    1402. 

  1402.       <pre>
    1403. 

  1403. _.isNull(null);
    1404. 

  1404. =&gt; true
    1405. 

  1405. _.isNull(undefined);
    1406. 

  1406. =&gt; false
    1407. 

  1407. </pre>
    1408. 

  1408. 

  1409.       <p id="isUndefined">
    1410. 

  1410.         <b class="header">isUndefined</b><code>_.isUndefined(value)</code>
    1411. 

  1411.         <br />
    1412. 

  1412.         Returns <i>true</i> if <b>value</b> is <i>undefined</i>.
    1413. 

  1413.       </p>
    1414. 

  1414.       <pre>
    1415. 

  1415. _.isUndefined(window.missingVariable);
    1416. 

  1416. =&gt; true
    1417. 

  1417. </pre>
    1418. 

  1418. 

  1419.       <h2 id="utility">Utility Functions</h2>
    1420. 

  1420. 

  1421.       <p id="noConflict">
    1422. 

  1422.         <b class="header">noConflict</b><code>_.noConflict()</code>
    1423. 

  1423.         <br />
    1424. 

  1424.         Give control of the "_" variable back to its previous owner. Returns
    1425. 

  1425.         a reference to the <b>Underscore</b> object.
    1426. 

  1426.       </p>
    1427. 

  1427.       <pre>
    1428. 

  1428. var underscore = _.noConflict();</pre>
    1429. 

  1429. 

  1430.       <p id="identity">
    1431. 

  1431.         <b class="header">identity</b><code>_.identity(value)</code>
    1432. 

  1432.         <br />
    1433. 

  1433.         Returns the same value that is used as the argument. In math:
    1434. 

  1434.         <tt>f(x) = x</tt><br />
    1435. 

  1435.         This function looks useless, but is used throughout Underscore as
    1436. 

  1436.         a default iterator.
    1437. 

  1437.       </p>
    1438. 

  1438.       <pre>
    1439. 

  1439. var moe = {name : 'moe'};
    1440. 

  1440. moe === _.identity(moe);
    1441. 

  1441. =&gt; true</pre>
    1442. 

  1442. 

  1443.       <p id="times">
    1444. 

  1444.         <b class="header">times</b><code>_.times(n, iterator, [context])</code>
    1445. 

  1445.         <br />
    1446. 

  1446.         Invokes the given iterator function <b>n</b> times. Each invocation of
    1447. 

  1447.         <b>iterator</b> is called with an <tt>index</tt> argument.
    1448. 

  1448.         <br />
    1449. 

  1449.         <i>Note: this example uses the <a href="#chaining">chaining syntax</a></i>.
    1450. 

  1450.       </p>
    1451. 

  1451.       <pre>
    1452. 

  1452. _(3).times(function(n){ genie.grantWishNumber(n); });</pre>
    1453. 

  1453. 

  1454.       <p id="random">
    1455. 

  1455.         <b class="header">random</b><code>_.random(min, max)</code>
    1456. 

  1456.         <br />
    1457. 

  1457.         Returns a random integer between <b>min</b> and <b>max</b>, inclusive.
    1458. 

  1458.         If you only pass one argument, it will return a number between <tt>0</tt>
    1459. 

  1459.         and that number.
    1460. 

  1460.       </p>
    1461. 

  1461.       <pre>
    1462. 

  1462. _.random(0, 100);
    1463. 

  1463. =&gt; 42</pre>
    1464. 

  1464. 

  1465.       <p id="mixin">
    1466. 

  1466.         <b class="header">mixin</b><code>_.mixin(object)</code>
    1467. 

  1467.         <br />
    1468. 

  1468.         Allows you to extend Underscore with your own utility functions. Pass
    1469. 

  1469.         a hash of <tt>{name: function}</tt> definitions to have your functions
    1470. 

  1470.         added to the Underscore object, as well as the OOP wrapper.
    1471. 

  1471.       </p>
    1472. 

  1472.       <pre>
    1473. 

  1473. _.mixin({
    1474. 

  1474.   capitalize : function(string) {
    1475. 

  1475.     return string.charAt(0).toUpperCase() + string.substring(1).toLowerCase();
    1476. 

  1476.   }
    1477. 

  1477. });
    1478. 

  1478. _("fabio").capitalize();
    1479. 

  1479. =&gt; "Fabio"
    1480. 

  1480. </pre>
    1481. 

  1481. 

  1482.       <p id="uniqueId">
    1483. 

  1483.         <b class="header">uniqueId</b><code>_.uniqueId([prefix])</code>
    1484. 

  1484.         <br />
    1485. 

  1485.         Generate a globally-unique id for client-side models or DOM elements
    1486. 

  1486.         that need one. If <b>prefix</b> is passed, the id will be appended to it.
    1487. 

  1487.         Without <b>prefix</b>, returns an integer.
    1488. 

  1488.       </p>
    1489. 

  1489.       <pre>
    1490. 

  1490. _.uniqueId('contact_');
    1491. 

  1491. =&gt; 'contact_104'</pre>
    1492. 

  1492. 

  1493.       <p id="escape">
    1494. 

  1494.         <b class="header">escape</b><code>_.escape(string)</code>
    1495. 

  1495.         <br />
    1496. 

  1496.         Escapes a string for insertion into HTML, replacing
    1497. 

  1497.         <tt>&amp;</tt>, <tt>&lt;</tt>, <tt>&gt;</tt>, <tt>&quot;</tt>, <tt>&#x27;</tt>, and <tt>&#x2F;</tt> characters.
    1498. 

  1498.       </p>
    1499. 

  1499.       <pre>
    1500. 

  1500. _.escape('Curly, Larry &amp; Moe');
    1501. 

  1501. =&gt; "Curly, Larry &amp;amp; Moe"</pre>
    1502. 

  1502. 

  1503.       <p id="unescape">
    1504. 

  1504.         <b class="header">unescape</b><code>_.unescape(string)</code>
    1505. 

  1505.         <br />
    1506. 

  1506.         The opposite of <a href="#escape"><b>escape</b></a>, replaces
    1507. 

  1507.         <tt>&amp;amp;</tt>, <tt>&amp;lt;</tt>, <tt>&amp;gt;</tt>,
    1508. 

  1508.         <tt>&amp;quot;</tt>, <tt>&amp;#x27;</tt>, and <tt>&amp;#x2F;</tt>
    1509. 

  1509.         with their unescaped counterparts.
    1510. 

  1510.       </p>
    1511. 

  1511.       <pre>
    1512. 

  1512. _.escape('Curly, Larry &amp;amp; Moe');
    1513. 

  1513. =&gt; "Curly, Larry &amp; Moe"</pre>
    1514. 

  1514. 

  1515.       <p id="result">
    1516. 

  1516.         <b class="header">result</b><code>_.result(object, property)</code>
    1517. 

  1517.         <br />
    1518. 

  1518.         If the value of the named property is a function then invoke it; otherwise, return it.
    1519. 

  1519.       </p>
    1520. 

  1520.       <pre>
    1521. 

  1521. var object = {cheese: 'crumpets', stuff: function(){ return 'nonsense'; }};
    1522. 

  1522. _.result(object, 'cheese');
    1523. 

  1523. =&gt; "crumpets"
    1524. 

  1524. _.result(object, 'stuff');
    1525. 

  1525. =&gt; "nonsense"</pre>
    1526. 

  1526. 

  1527.       <p id="template">
    1528. 

  1528.         <b class="header">template</b><code>_.template(templateString, [data], [settings])</code>
    1529. 

  1529.         <br />
    1530. 

  1530.         Compiles JavaScript templates into functions that can be evaluated
    1531. 

  1531.         for rendering. Useful for rendering complicated bits of HTML from JSON
    1532. 

  1532.         data sources. Template functions can both interpolate variables, using
    1533. 

  1533.         <tt>&lt;%= &hellip; %&gt;</tt>, as well as execute arbitrary JavaScript code, with
    1534. 

  1534.         <tt>&lt;% &hellip; %&gt;</tt>. If you wish to interpolate a value, and have
    1535. 

  1535.         it be HTML-escaped, use <tt>&lt;%- &hellip; %&gt;</tt> When you evaluate a template function, pass in a
    1536. 

  1536.         <b>data</b> object that has properties corresponding to the template's free
    1537. 

  1537.         variables. If you're writing a one-off, you can pass the <b>data</b>
    1538. 

  1538.         object as the second parameter to <b>template</b> in order to render
    1539. 

  1539.         immediately instead of returning a template function.  The <b>settings</b> argument
    1540. 

  1540.         should be a hash containing any <tt>_.templateSettings</tt> that should be overridden.
    1541. 

  1541.       </p>
    1542. 

  1542. 

  1543.       <pre>
    1544. 

  1544. var compiled = _.template("hello: &lt;%= name %&gt;");
    1545. 

  1545. compiled({name : 'moe'});
    1546. 

  1546. =&gt; "hello: moe"
    1547. 

  1547. 

  1548. var list = "&lt;% _.each(people, function(name) { %&gt; &lt;li&gt;&lt;%= name %&gt;&lt;/li&gt; &lt;% }); %&gt;";
    1549. 

  1549. _.template(list, {people : ['moe', 'curly', 'larry']});
    1550. 

  1550. =&gt; "&lt;li&gt;moe&lt;/li&gt;&lt;li&gt;curly&lt;/li&gt;&lt;li&gt;larry&lt;/li&gt;"
    1551. 

  1551. 

  1552. var template = _.template("&lt;b&gt;&lt;%- value %&gt;&lt;/b&gt;");
    1553. 

  1553. template({value : '&lt;script&gt;'});
    1554. 

  1554. =&gt; "&lt;b&gt;&amp;lt;script&amp;gt;&lt;/b&gt;"</pre>
    1555. 

  1555. 

  1556.       <p>
    1557. 

  1557.         You can also use <tt>print</tt> from within JavaScript code.  This is
    1558. 

  1558.         sometimes more convenient than using <tt>&lt;%= ... %&gt;</tt>.
    1559. 

  1559.       </p>
    1560. 

  1560. 

  1561.       <pre>
    1562. 

  1562. var compiled = _.template("&lt;% print('Hello ' + epithet); %&gt;");
    1563. 

  1563. compiled({epithet: "stooge"});
    1564. 

  1564. =&gt; "Hello stooge."</pre>
    1565. 

  1565. 

  1566.       <p>
    1567. 

  1567.         If ERB-style delimiters aren't your cup of tea, you can change Underscore's
    1568. 

  1568.         template settings to use different symbols to set off interpolated code.
    1569. 

  1569.         Define an <b>interpolate</b> regex to match expressions that should be
    1570. 

  1570.         interpolated verbatim, an <b>escape</b> regex to match expressions that should
    1571. 

  1571.         be inserted after being HTML escaped, and an <b>evaluate</b> regex to match
    1572. 

  1572.         expressions that should be evaluated without insertion into the resulting
    1573. 

  1573.         string. You may define or omit any combination of the three.
    1574. 

  1574.         For example, to perform
    1575. 

  1575.         <a href="http://github.com/janl/mustache.js#readme">Mustache.js</a>
    1576. 

  1576.         style templating:
    1577. 

  1577.       </p>
    1578. 

  1578. 

  1579.       <pre>
    1580. 

  1580. _.templateSettings = {
    1581. 

  1581.   interpolate : /\{\{(.+?)\}\}/g
    1582. 

  1582. };
    1583. 

  1583. 

  1584. var template = _.template("Hello {{ name }}!");
    1585. 

  1585. template({name : "Mustache"});
    1586. 

  1586. =&gt; "Hello Mustache!"</pre>
    1587. 

  1587. 

  1588.       <p>
    1589. 

  1589.         By default, <b>template</b> places the values from your data in the local scope
    1590. 

  1590.         via the <tt>with</tt> statement.  However, you can specify a single variable name
    1591. 

  1591.         with the <b>variable</b> setting. This can significantly improve the speed
    1592. 

  1592.         at which a template is able to render.
    1593. 

  1593.       </p>
    1594. 

  1594. 

  1595.       <pre>
    1596. 

  1596. _.template("Using 'with': <%= data.answer %>", {answer: 'no'}, {variable: 'data'});
    1597. 

  1597. =&gt; "Using 'with': no"</pre>
    1598. 

  1598. 

  1599.       <p>
    1600. 

  1600.         Precompiling your templates can be a big help when debugging errors you can't
    1601. 

  1601.         reproduce.  This is because precompiled templates can provide line numbers and
    1602. 

  1602.         a stack trace, something that is not possible when compiling templates on the client.
    1603. 

  1603.         The <b>source</b> property is available on the compiled template
    1604. 

  1604.         function for easy precompilation.
    1605. 

  1605.       </p>
    1606. 

  1606. 

  1607.       <pre>&lt;script&gt;
    1608. 

  1608.   JST.project = <%= _.template(jstText).source %>;
    1609. 

  1609. &lt;/script&gt;</pre>
    1610. 

  1610. 

  1611. 

  1612.       <h2 id="chaining">Chaining</h2>
    1613. 

  1613. 

  1614.       <p>
    1615. 

  1615.         You can use Underscore in either an object-oriented or a functional style,
    1616. 

  1616.         depending on your preference. The following two lines of code are
    1617. 

  1617.         identical ways to double a list of numbers.
    1618. 

  1618.       </p>
    1619. 

  1619. 

  1620.     <pre>
    1621. 

  1621. _.map([1, 2, 3], function(n){ return n * 2; });
    1622. 

  1622. _([1, 2, 3]).map(function(n){ return n * 2; });</pre>
    1623. 

  1623. 

  1624.       <p>
    1625. 

  1625.         Calling <tt>chain</tt> will cause all future method calls to return
    1626. 

  1626.         wrapped objects. When you've finished the computation, use
    1627. 

  1627.         <tt>value</tt> to retrieve the final value. Here's an example of chaining
    1628. 

  1628.         together a <b>map/flatten/reduce</b>, in order to get the word count of
    1629. 

  1629.         every word in a song.
    1630. 

  1630.       </p>
    1631. 

  1631. 

  1632. <pre>
    1633. 

  1633. var lyrics = [
    1634. 

  1634.   {line : 1, words : "I'm a lumberjack and I'm okay"},
    1635. 

  1635.   {line : 2, words : "I sleep all night and I work all day"},
    1636. 

  1636.   {line : 3, words : "He's a lumberjack and he's okay"},
    1637. 

  1637.   {line : 4, words : "He sleeps all night and he works all day"}
    1638. 

  1638. ];
    1639. 

  1639. 

  1640. _.chain(lyrics)
    1641. 

  1641.   .map(function(line) { return line.words.split(' '); })
    1642. 

  1642.   .flatten()
    1643. 

  1643.   .reduce(function(counts, word) {
    1644. 

  1644.     counts[word] = (counts[word] || 0) + 1;
    1645. 

  1645.     return counts;
    1646. 

  1646. }, {}).value();
    1647. 

  1647. 

  1648. =&gt; {lumberjack : 2, all : 4, night : 2 ... }</pre>
    1649. 

  1649. 

  1650.       <p>
    1651. 

  1651.         In addition, the
    1652. 

  1652.         <a href="https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Array/prototype">Array prototype's methods</a>
    1653. 

  1653.         are proxied through the chained Underscore object, so you can slip a
    1654. 

  1654.         <tt>reverse</tt> or a <tt>push</tt> into your chain, and continue to
    1655. 

  1655.         modify the array.
    1656. 

  1656.       </p>
    1657. 

  1657. 

  1658.       <p id="chain">
    1659. 

  1659.         <b class="header">chain</b><code>_.chain(obj)</code>
    1660. 

  1660.         <br />
    1661. 

  1661.         Returns a wrapped object. Calling methods on this object will continue
    1662. 

  1662.         to return wrapped objects until <tt>value</tt> is used.
    1663. 

  1663.       </p>
    1664. 

  1664.       <pre>
    1665. 

  1665. var stooges = [{name : 'curly', age : 25}, {name : 'moe', age : 21}, {name : 'larry', age : 23}];
    1666. 

  1666. var youngest = _.chain(stooges)
    1667. 

  1667.   .sortBy(function(stooge){ return stooge.age; })
    1668. 

  1668.   .map(function(stooge){ return stooge.name + ' is ' + stooge.age; })
    1669. 

  1669.   .first()
    1670. 

  1670.   .value();
    1671. 

  1671. =&gt; "moe is 21"
    1672. 

  1672. </pre>
    1673. 

  1673. 

  1674.       <p id="value">
    1675. 

  1675.         <b class="header">value</b><code>_(obj).value()</code>
    1676. 

  1676.         <br />
    1677. 

  1677.         Extracts the value of a wrapped object.
    1678. 

  1678.       </p>
    1679. 

  1679.       <pre>
    1680. 

  1680. _([1, 2, 3]).value();
    1681. 

  1681. =&gt; [1, 2, 3]
    1682. 

  1682. </pre>
    1683. 

  1683. 

  1684.       <h2 id="links">Links &amp; Suggested Reading</h2>
    1685. 

  1685. 

  1686.       <p>
    1687. 

  1687.         The Underscore documentation is also available in
    1688. 

  1688.         <a href="http://learning.github.com/underscore/">Simplified Chinese</a>.
    1689. 

  1689.       </p>
    1690. 

  1690. 

  1691.       <p>
    1692. 

  1692.         <a href="http://mirven.github.com/underscore.lua/">Underscore.lua</a>,
    1693. 

  1693.         a Lua port of the functions that are applicable in both languages.
    1694. 

  1694.         Includes OOP-wrapping and chaining.
    1695. 

  1695.         (<a href="http://github.com/mirven/underscore.lua">source</a>)
    1696. 

  1696.       </p>
    1697. 

  1697. 

  1698.       <p>
    1699. 

  1699.         <a href="http://underscorem.org">Underscore.m</a>, an Objective-C port
    1700. 

  1700.         of many of the Underscore.js functions, using a syntax that encourages
    1701. 

  1701.         chaining.
    1702. 

  1702.         (<a href="https://github.com/robb/Underscore.m">source</a>)
    1703. 

  1703.       </p>
    1704. 

  1704. 

  1705.       <p>
    1706. 

  1706.         <a href="http://kmalakoff.github.com/_.m/">_.m</a>, an alternative
    1707. 

  1707.         Objective-C port that tries to stick a little closer to the original
    1708. 

  1708.         Underscore.js API.
    1709. 

  1709.         (<a href="https://github.com/kmalakoff/_.m">source</a>)
    1710. 

  1710.       </p>
    1711. 

  1711. 

  1712.       <p>
    1713. 

  1713.         <a href="http://brianhaveri.github.com/Underscore.php/">Underscore.php</a>,
    1714. 

  1714.         a PHP port of the functions that are applicable in both languages.
    1715. 

  1715.         Includes OOP-wrapping and chaining.
    1716. 

  1716.         (<a href="http://github.com/brianhaveri/Underscore.php">source</a>)
    1717. 

  1717.       </p>
    1718. 

  1718. 

  1719.       <p>
    1720. 

  1720.         <a href="http://vti.github.com/underscore-perl/">Underscore-perl</a>,
    1721. 

  1721.         a Perl port of many of the Underscore.js functions,
    1722. 

  1722.         aimed at on Perl hashes and arrays.
    1723. 

  1723.         (<a href="https://github.com/vti/underscore-perl/">source</a>)
    1724. 

  1724.       </p>
    1725. 

  1725. 

  1726.       <p>
    1727. 

  1727.         <a href="http://russplaysguitar.github.com/UnderscoreCF/">Underscore.cfc</a>,
    1728. 

  1728.         a Coldfusion port of many of the Underscore.js functions.
    1729. 

  1729.         (<a href="https://github.com/russplaysguitar/underscorecf">source</a>)
    1730. 

  1730.       </p>
    1731. 

  1731. 

  1732.       <p>
    1733. 

  1733.         <a href="https://github.com/edtsech/underscore.string">Underscore.string</a>,
    1734. 

  1734.         an Underscore extension that adds functions for string-manipulation:
    1735. 

  1735.         <tt>trim</tt>, <tt>startsWith</tt>, <tt>contains</tt>, <tt>capitalize</tt>,
    1736. 

  1736.         <tt>reverse</tt>, <tt>sprintf</tt>, and more.
    1737. 

  1737.       </p>
    1738. 

  1738. 

  1739.       <p>
    1740. 

  1740.         Ruby's <a href="http://ruby-doc.org/core/classes/Enumerable.html">Enumerable</a> module.
    1741. 

  1741.       </p>
    1742. 

  1742. 

  1743.       <p>
    1744. 

  1744.         <a href="http://www.prototypejs.org/">Prototype.js</a>, which provides
    1745. 

  1745.         JavaScript with collection functions in the manner closest to Ruby's Enumerable.
    1746. 

  1746.       </p>
    1747. 

  1747. 

  1748.       <p>
    1749. 

  1749.         Oliver Steele's
    1750. 

  1750.         <a href="http://osteele.com/sources/javascript/functional/">Functional JavaScript</a>,
    1751. 

  1751.         which includes comprehensive higher-order function support as well as string lambdas.
    1752. 

  1752.       </p>
    1753. 

  1753. 

  1754.       <p>
    1755. 

  1755.         Michael Aufreiter's <a href="http://github.com/michael/data">Data.js</a>,
    1756. 

  1756.         a data manipulation + persistence library for JavaScript.
    1757. 

  1757.       </p>
    1758. 

  1758. 

  1759.       <p>
    1760. 

  1760.         Python's <a href="http://docs.python.org/library/itertools.html">itertools</a>.
    1761. 

  1761.       </p>
    1762. 

  1762. 

  1763.       <h2 id="changelog">Change Log</h2>
    1764. 

  1764. 

  1765.       <p>
    1766. 

  1766.         <b class="header">1.4.2</b> &mdash; <small><i>Oct. 1, 2012</i></small>  &mdash; <a href="https://github.com/documentcloud/underscore/compare/1.4.1...1.4.2">Diff</a><br />
    1767. 

  1767.         <ul>
    1768. 

  1768.           <li>
    1769. 

  1769.             For backwards compatibility, returned to pre-1.4.0 behavior when
    1770. 

  1770.             passing <tt>null</tt> to iteration functions. They now become no-ops
    1771. 

  1771.             again.
    1772. 

  1772.           </li>
    1773. 

  1773.         </ul>
    1774. 

  1774.       </p>
    1775. 

  1775. 

  1776.       <p>
    1777. 

  1777.         <b class="header">1.4.1</b> &mdash; <small><i>Oct. 1, 2012</i></small>  &mdash; <a href="https://github.com/documentcloud/underscore/compare/1.4.0...1.4.1">Diff</a><br />
    1778. 

  1778.         <ul>
    1779. 

  1779.           <li>
    1780. 

  1780.             Fixed a 1.4.0 regression in the <tt>lastIndexOf</tt> function.
    1781. 

  1781.           </li>
    1782. 

  1782.         </ul>
    1783. 

  1783.       </p>
    1784. 

  1784. 

  1785.       <p>
    1786. 

  1786.         <b class="header">1.4.0</b> &mdash; <small><i>Sept. 27, 2012</i></small>  &mdash; <a href="https://github.com/documentcloud/underscore/compare/1.3.3...1.4.0">Diff</a><br />
    1787. 

  1787.         <ul>
    1788. 

  1788.           <li>
    1789. 

  1789.             Added a <tt>pairs</tt> function, for turning a JavaScript object
    1790. 

  1790.             into <tt>[key, value]</tt> pairs ... as well as an <tt>object</tt>
    1791. 

  1791.             function, for converting an array of <tt>[key, value]</tt> pairs
    1792. 

  1792.             into an object.
    1793. 

  1793.           </li>
    1794. 

  1794.           <li>
    1795. 

  1795.             Added a <tt>countBy</tt> function, for counting the number of objects
    1796. 

  1796.             in a list that match a certain criteria.
    1797. 

  1797.           </li>
    1798. 

  1798.           <li>
    1799. 

  1799.             Added an <tt>invert</tt> function, for performing a simple inversion
    1800. 

  1800.             of the keys and values in an object.
    1801. 

  1801.           </li>
    1802. 

  1802.           <li>
    1803. 

  1803.             Added a <tt>where</tt> function, for easy cases of filtering a list
    1804. 

  1804.             for objects with specific values.
    1805. 

  1805.           </li>
    1806. 

  1806.           <li>
    1807. 

  1807.             Added an <tt>omit</tt> function, for filtering an object to remove
    1808. 

  1808.             certain keys.
    1809. 

  1809.           </li>
    1810. 

  1810.           <li>
    1811. 

  1811.             Added a <tt>random</tt> function, to return a random number in a
    1812. 

  1812.             given range.
    1813. 

  1813.           </li>
    1814. 

  1814.           <li>
    1815. 

  1815.             <tt>_.debounce</tt>'d functions now return their last updated value,
    1816. 

  1816.             just like <tt>_.throttle</tt>'d functions do.
    1817. 

  1817.           </li>
    1818. 

  1818.           <li>
    1819. 

  1819.             The <tt>sortBy</tt> function now runs a stable sort algorithm.
    1820. 

  1820.           </li>
    1821. 

  1821.           <li>
    1822. 

  1822.             Added the optional <tt>fromIndex</tt> option to <tt>indexOf</tt> and
    1823. 

  1823.             <tt>lastIndexOf</tt>.
    1824. 

  1824.           </li>
    1825. 

  1825.           <li>
    1826. 

  1826.             "Sparse" arrays are no longer supported in Underscore iteration
    1827. 

  1827.             functions. Use a <tt>for</tt> loop instead (or better yet, an object).
    1828. 

  1828.           </li>
    1829. 

  1829.           <li>
    1830. 

  1830.             The <tt>min</tt> and <tt>max</tt> functions may now be called on
    1831. 

  1831.             <i>very</i> large arrays.
    1832. 

  1832.           </li>
    1833. 

  1833.           <li>
    1834. 

  1834.             Interpolation in templates now represents <tt>null</tt> and
    1835. 

  1835.             <tt>undefined</tt> as the empty string.
    1836. 

  1836.           </li>
    1837. 

  1837.           <li>
    1838. 

  1838.             <del>Underscore iteration functions no longer accept <tt>null</tt> values
    1839. 

  1839.             as a no-op argument. You'll get an early error instead.</del>
    1840. 

  1840.           </li>
    1841. 

  1841.           <li>
    1842. 

  1842.             A number of edge-cases fixes and tweaks, which you can spot in the
    1843. 

  1843.             <a href="https://github.com/documentcloud/underscore/compare/1.3.3...1.4.0">diff</a>.
    1844. 

  1844.             Depending on how you're using Underscore, <b>1.4.0</b> may be more
    1845. 

  1845.             backwards-incompatible than usual &mdash; please test when you upgrade.
    1846. 

  1846.           </li>
    1847. 

  1847.         </ul>
    1848. 

  1848.       </p>
    1849. 

  1849. 

  1850.       <p>
    1851. 

  1851.         <b class="header">1.3.3</b> &mdash; <small><i>April 10, 2012</i></small><br />
    1852. 

  1852.         <ul>
    1853. 

  1853.           <li>
    1854. 

  1854.             Many improvements to <tt>_.template</tt>, which now provides the
    1855. 

  1855.             <tt>source</tt> of the template function as a property, for potentially
    1856. 

  1856.             even more efficient pre-compilation on the server-side. You may now
    1857. 

  1857.             also set the <tt>variable</tt> option when creating a template,
    1858. 

  1858.             which will cause your passed-in data to be made available under the
    1859. 

  1859.             variable you named, instead of using a <tt>with</tt> statement &mdash;
    1860. 

  1860.             significantly improving the speed of rendering the template.
    1861. 

  1861.           </li>
    1862. 

  1862.           <li>
    1863. 

  1863.             Added the <tt>pick</tt> function, which allows you to filter an
    1864. 

  1864.             object literal with a whitelist of allowed property names.
    1865. 

  1865.           </li>
    1866. 

  1866.           <li>
    1867. 

  1867.             Added the <tt>result</tt> function, for convenience when working
    1868. 

  1868.             with APIs that allow either functions or raw properties.
    1869. 

  1869.           </li>
    1870. 

  1870.           <li>
    1871. 

  1871.             Added the <tt>isFinite</tt> function, because sometimes knowing that
    1872. 

  1872.             a value is a number just ain't quite enough.
    1873. 

  1873.           </li>
    1874. 

  1874.           <li>
    1875. 

  1875.             The <tt>sortBy</tt> function may now also be passed the string name
    1876. 

  1876.             of a property to use as the sort order on each object.
    1877. 

  1877.           </li>
    1878. 

  1878.           <li>
    1879. 

  1879.             Fixed <tt>uniq</tt> to work with sparse arrays.
    1880. 

  1880.           </li>
    1881. 

  1881.           <li>
    1882. 

  1882.             The <tt>difference</tt> function now performs a shallow flatten
    1883. 

  1883.             instead of a deep one when computing array differences.
    1884. 

  1884.           </li>
    1885. 

  1885.           <li>
    1886. 

  1886.             The <tt>debounce</tt> function now takes an <tt>immediate</tt>
    1887. 

  1887.             parameter, which will cause the callback to fire on the leading
    1888. 

  1888.             instead of the trailing edge.
    1889. 

  1889.           </li>
    1890. 

  1890.         </ul>
    1891. 

  1891.       </p>
    1892. 

  1892. 

  1893.       <p>
    1894. 

  1894.         <b class="header">1.3.1</b> &mdash; <small><i>Jan. 23, 2012</i></small><br />
    1895. 

  1895.         <ul>
    1896. 

  1896.           <li>
    1897. 

  1897.             Added an <tt>_.has</tt> function, as a safer way to use <tt>hasOwnProperty</tt>.
    1898. 

  1898.           </li>
    1899. 

  1899.           <li>
    1900. 

  1900.             Added <tt>_.collect</tt> as an alias for <tt>_.map</tt>. Smalltalkers, rejoice.
    1901. 

  1901.           </li>
    1902. 

  1902.           <li>
    1903. 

  1903.             Reverted an old change so that <tt>_.extend</tt> will correctly copy
    1904. 

  1904.             over keys with undefined values again.
    1905. 

  1905.           </li>
    1906. 

  1906.           <li>
    1907. 

  1907.             Bugfix to stop escaping slashes within interpolations in <tt>_.template</tt>.
    1908. 

  1908.           </li>
    1909. 

  1909.         </ul>
    1910. 

  1910.       </p>
    1911. 

  1911. 

  1912.       <p>
    1913. 

  1913.         <b class="header">1.3.0</b> &mdash; <small><i>Jan. 11, 2012</i></small><br />
    1914. 

  1914.         <ul>
    1915. 

  1915.           <li>
    1916. 

  1916.             Removed AMD (RequireJS) support from Underscore. If you'd like to use
    1917. 

  1917.             Underscore with RequireJS, you can load it as a normal script, wrap
    1918. 

  1918.             or patch your copy, or download a forked version.
    1919. 

  1919.           </li>
    1920. 

  1920.         </ul>
    1921. 

  1921.       </p>
    1922. 

  1922. 

  1923.       <p>
    1924. 

  1924.         <b class="header">1.2.4</b> &mdash; <small><i>Jan. 4, 2012</i></small><br />
    1925. 

  1925.         <ul>
    1926. 

  1926.           <li>
    1927. 

  1927.             You now can (and probably should, as it's simpler)
    1928. 

  1928.             write <tt>_.chain(list)</tt>
    1929. 

  1929.             instead of <tt>_(list).chain()</tt>.
    1930. 

  1930.           </li>
    1931. 

  1931.           <li>
    1932. 

  1932.             Fix for escaped characters in Underscore templates, and for supporting
    1933. 

  1933.             customizations of <tt>_.templateSettings</tt> that only define one or
    1934. 

  1934.             two of the required regexes.
    1935. 

  1935.           </li>
    1936. 

  1936.           <li>
    1937. 

  1937.             Fix for passing an array as the first argument to an <tt>_.wrap</tt>'d function.
    1938. 

  1938.           </li>
    1939. 

  1939.           <li>
    1940. 

  1940.             Improved compatibility with ClojureScript, which adds a <tt>call</tt>
    1941. 

  1941.             function to <tt>String.prototype</tt>.
    1942. 

  1942.           </li>
    1943. 

  1943.         </ul>
    1944. 

  1944.       </p>
    1945. 

  1945. 

  1946.       <p>
    1947. 

  1947.         <b class="header">1.2.3</b> &mdash; <small><i>Dec. 7, 2011</i></small><br />
    1948. 

  1948.         <ul>
    1949. 

  1949.           <li>
    1950. 

  1950.             Dynamic scope is now preserved for compiled <tt>_.template</tt> functions,
    1951. 

  1951.             so you can use the value of <tt>this</tt> if you like.
    1952. 

  1952.           </li>
    1953. 

  1953.           <li>
    1954. 

  1954.             Sparse array support of <tt>_.indexOf</tt>, <tt>_.lastIndexOf</tt>.
    1955. 

  1955.           </li>
    1956. 

  1956.           <li>
    1957. 

  1957.             Both <tt>_.reduce</tt> and <tt>_.reduceRight</tt> can now be passed an
    1958. 

  1958.             explicitly <tt>undefined</tt> value. (There's no reason why you'd
    1959. 

  1959.             want to do this.)
    1960. 

  1960.           </li>
    1961. 

  1961.         </ul>
    1962. 

  1962.       </p>
    1963. 

  1963. 

  1964.       <p>
    1965. 

  1965.         <b class="header">1.2.2</b> &mdash; <small><i>Nov. 14, 2011</i></small><br />
    1966. 

  1966.         <ul>
    1967. 

  1967.           <li>
    1968. 

  1968.             Continued tweaks to <tt>_.isEqual</tt> semantics. Now JS primitives are
    1969. 

  1969.             considered equivalent to their wrapped versions, and arrays are compared
    1970. 

  1970.             by their numeric properties only <small>(#351)</small>.
    1971. 

  1971.           </li>
    1972. 

  1972.           <li>
    1973. 

  1973.             <tt>_.escape</tt> no longer tries to be smart about not double-escaping
    1974. 

  1974.             already-escaped HTML entities. Now it just escapes regardless <small>(#350)</small>.
    1975. 

  1975.           </li>
    1976. 

  1976.           <li>
    1977. 

  1977.             In <tt>_.template</tt>, you may now leave semicolons out of evaluated
    1978. 

  1978.             statements if you wish: <tt>&lt;% }) %&gt;</tt> <small>(#369)</small>.
    1979. 

  1979.           </li>
    1980. 

  1980.           <li>
    1981. 

  1981.             <tt>_.after(callback, 0)</tt> will now trigger the callback immediately,
    1982. 

  1982.             making "after" easier to use with asynchronous APIs <small>(#366)</small>.
    1983. 

  1983.           </li>
    1984. 

  1984.         </ul>
    1985. 

  1985.       </p>
    1986. 

  1986. 

  1987.       <p>
    1988. 

  1988.         <b class="header">1.2.1</b> &mdash; <small><i>Oct. 24, 2011</i></small><br />
    1989. 

  1989.         <ul>
    1990. 

  1990.           <li>
    1991. 

  1991.             Several important bug fixes for <tt>_.isEqual</tt>, which should now
    1992. 

  1992.             do better on mutated Arrays, and on non-Array objects with
    1993. 

  1993.             <tt>length</tt> properties. <small>(#329)</small>
    1994. 

  1994.           </li>
    1995. 

  1995.           <li>
    1996. 

  1996.             <b>jrburke</b> contributed Underscore exporting for AMD module loaders,
    1997. 

  1997.             and <b>tonylukasavage</b> for Appcelerator Titanium.
    1998. 

  1998.             <small>(#335, #338)</small>
    1999. 

  1999.           </li>
    2000. 

  2000.           <li>
    2001. 

  2001.             You can now <tt>_.groupBy(list, 'property')</tt> as a shortcut for
    2002. 

  2002.             grouping values by a particular common property.
    2003. 

  2003.           </li>
    2004. 

  2004.           <li>
    2005. 

  2005.             <tt>_.throttle</tt>'d functions now fire immediately upon invocation,
    2006. 

  2006.             and are rate-limited thereafter <small>(#170, #266)</small>.
    2007. 

  2007.           </li>
    2008. 

  2008.           <li>
    2009. 

  2009.             Most of the <tt>_.is[Type]</tt> checks no longer ducktype.
    2010. 

  2010.           </li>
    2011. 

  2011.           <li>
    2012. 

  2012.             The <tt>_.bind</tt> function now also works on constructors, a-la
    2013. 

  2013.             ES5 ... but you would never want to use <tt>_.bind</tt> on a
    2014. 

  2014.             constructor function.
    2015. 

  2015.           </li>
    2016. 

  2016.           <li>
    2017. 

  2017.             <tt>_.clone</tt> no longer wraps non-object types in Objects.
    2018. 

  2018.           </li>
    2019. 

  2019.           <li>
    2020. 

  2020.             <tt>_.find</tt> and <tt>_.filter</tt> are now the preferred names for
    2021. 

  2021.             <tt>_.detect</tt> and <tt>_.select</tt>.
    2022. 

  2022.           </li>
    2023. 

  2023.         </ul>
    2024. 

  2024.       </p>
    2025. 

  2025. 

  2026.       <p>
    2027. 

  2027.         <b class="header">1.2.0</b> &mdash; <small><i>Oct. 5, 2011</i></small><br />
    2028. 

  2028.         <ul>
    2029. 

  2029.           <li>
    2030. 

  2030.             The <tt>_.isEqual</tt> function now
    2031. 

  2031.             supports true deep equality comparisons, with checks for cyclic structures,
    2032. 

  2032.             thanks to Kit Cambridge.
    2033. 

  2033.           </li>
    2034. 

  2034.           <li>
    2035. 

  2035.             Underscore templates now support HTML escaping interpolations, using
    2036. 

  2036.             <tt>&lt;%- ... %&gt;</tt> syntax.
    2037. 

  2037.           </li>
    2038. 

  2038.           <li>
    2039. 

  2039.             Ryan Tenney contributed <tt>_.shuffle</tt>, which uses a modified
    2040. 

  2040.             Fisher-Yates to give you a shuffled copy of an array.
    2041. 

  2041.           </li>
    2042. 

  2042.           <li>
    2043. 

  2043.             <tt>_.uniq</tt> can now be passed an optional iterator, to determine by
    2044. 

  2044.             what criteria an object should be considered unique.
    2045. 

  2045.           </li>
    2046. 

  2046.           <li>
    2047. 

  2047.             <tt>_.last</tt> now takes an optional argument which will return the last
    2048. 

  2048.             N elements of the list.
    2049. 

  2049.           </li>
    2050. 

  2050.           <li>
    2051. 

  2051.             A new <tt>_.initial</tt> function was added, as a mirror of <tt>_.rest</tt>,
    2052. 

  2052.             which returns all the initial values of a list (except the last N).
    2053. 

  2053.           </li>
    2054. 

  2054.         </ul>
    2055. 

  2055.       </p>
    2056. 

  2056. 

  2057.       <p>
    2058. 

  2058.         <b class="header">1.1.7</b> &mdash; <small><i>July 13, 2011</i></small><br />
    2059. 

  2059.         Added <tt>_.groupBy</tt>, which aggregates a collection into groups of like items.
    2060. 

  2060.         Added <tt>_.union</tt> and <tt>_.difference</tt>, to complement the
    2061. 

  2061.         (re-named) <tt>_.intersection</tt>.
    2062. 

  2062.         Various improvements for support of sparse arrays.
    2063. 

  2063.         <tt>_.toArray</tt> now returns a clone, if directly passed an array.
    2064. 

  2064.         <tt>_.functions</tt> now also returns the names of functions that are present
    2065. 

  2065.         in the prototype chain.
    2066. 

  2066.       </p>
    2067. 

  2067. 

  2068.       <p>
    2069. 

  2069.         <b class="header">1.1.6</b> &mdash; <small><i>April 18, 2011</i></small><br />
    2070. 

  2070.         Added <tt>_.after</tt>, which will return a function that only runs after
    2071. 

  2071.         first being called a specified number of times.
    2072. 

  2072.         <tt>_.invoke</tt> can now take a direct function reference.
    2073. 

  2073.         <tt>_.every</tt> now requires an iterator function to be passed, which
    2074. 

  2074.         mirrors the ECMA5 API.
    2075. 

  2075.         <tt>_.extend</tt> no longer copies keys when the value is undefined.
    2076. 

  2076.         <tt>_.bind</tt> now errors when trying to bind an undefined value.
    2077. 

  2077.       </p>
    2078. 

  2078. 

  2079.       <p>
    2080. 

  2080.         <b class="header">1.1.5</b> &mdash; <small><i>Mar 20, 2011</i></small><br />
    2081. 

  2081.         Added an <tt>_.defaults</tt> function, for use merging together JS objects
    2082. 

  2082.         representing default options.
    2083. 

  2083.         Added an <tt>_.once</tt> function, for manufacturing functions that should
    2084. 

  2084.         only ever execute a single time.
    2085. 

  2085.         <tt>_.bind</tt> now delegates to the native ECMAScript 5 version,
    2086. 

  2086.         where available.
    2087. 

  2087.         <tt>_.keys</tt> now throws an error when used on non-Object values, as in
    2088. 

  2088.         ECMAScript 5.
    2089. 

  2089.         Fixed a bug with <tt>_.keys</tt> when used over sparse arrays.
    2090. 

  2090.       </p>
    2091. 

  2091. 

  2092.       <p>
    2093. 

  2093.         <b class="header">1.1.4</b> &mdash; <small><i>Jan 9, 2011</i></small><br />
    2094. 

  2094.         Improved compliance with ES5's Array methods when passing <tt>null</tt>
    2095. 

  2095.         as a value. <tt>_.wrap</tt> now correctly sets <tt>this</tt> for the
    2096. 

  2096.         wrapped function. <tt>_.indexOf</tt> now takes an optional flag for
    2097. 

  2097.         finding the insertion index in an array that is guaranteed to already
    2098. 

  2098.         be sorted. Avoiding the use of <tt>.callee</tt>, to allow <tt>_.isArray</tt>
    2099. 

  2099.         to work properly in ES5's strict mode.
    2100. 

  2100.       </p>
    2101. 

  2101. 

  2102.       <p>
    2103. 

  2103.         <b class="header">1.1.3</b> &mdash; <small><i>Dec 1, 2010</i></small><br />
    2104. 

  2104.         In CommonJS, Underscore may now be required with just: <br />
    2105. 

  2105.         <tt>var _ = require("underscore")</tt>.
    2106. 

  2106.         Added <tt>_.throttle</tt> and <tt>_.debounce</tt> functions.
    2107. 

  2107.         Removed <tt>_.breakLoop</tt>, in favor of an ECMA5-style un-<i>break</i>-able
    2108. 

  2108.         each implementation &mdash; this removes the try/catch, and you'll now have
    2109. 

  2109.         better stack traces for exceptions that are thrown within an Underscore iterator.
    2110. 

  2110.         Improved the <b>isType</b> family of functions for better interoperability
    2111. 

  2111.         with Internet Explorer host objects.
    2112. 

  2112.         <tt>_.template</tt> now correctly escapes backslashes in templates.
    2113. 

  2113.         Improved <tt>_.reduce</tt> compatibility with the ECMA5 version:
    2114. 

  2114.         if you don't pass an initial value, the first item in the collection is used.
    2115. 

  2115.         <tt>_.each</tt> no longer returns the iterated collection, for improved
    2116. 

  2116.         consistency with ES5's <tt>forEach</tt>.
    2117. 

  2117.       </p>
    2118. 

  2118. 

  2119.       <p>
    2120. 

  2120.         <b class="header">1.1.2</b><br />
    2121. 

  2121.         Fixed <tt>_.contains</tt>, which was mistakenly pointing at
    2122. 

  2122.         <tt>_.intersect</tt> instead of <tt>_.include</tt>, like it should
    2123. 

  2123.         have been. Added <tt>_.unique</tt> as an alias for <tt>_.uniq</tt>.
    2124. 

  2124.       </p>
    2125. 

  2125. 

  2126.       <p>
    2127. 

  2127.         <b class="header">1.1.1</b><br />
    2128. 

  2128.         Improved the speed of <tt>_.template</tt>, and its handling of multiline
    2129. 

  2129.         interpolations. Ryan Tenney contributed optimizations to many Underscore
    2130. 

  2130.         functions. An annotated version of the source code is now available.
    2131. 

  2131.       </p>
    2132. 

  2132. 

  2133.       <p>
    2134. 

  2134.         <b class="header">1.1.0</b><br />
    2135. 

  2135.         The method signature of <tt>_.reduce</tt> has been changed to match
    2136. 

  2136.         the ECMAScript 5 signature, instead of the Ruby/Prototype.js version.
    2137. 

  2137.         This is a backwards-incompatible change. <tt>_.template</tt> may now be
    2138. 

  2138.         called with no arguments, and preserves whitespace. <tt>_.contains</tt>
    2139. 

  2139.         is a new alias for <tt>_.include</tt>.
    2140. 

  2140.       </p>
    2141. 

  2141. 

  2142.       <p>
    2143. 

  2143.         <b class="header">1.0.4</b><br />
    2144. 

  2144.         <a href="http://themoell.com/">Andri Möll</a> contributed the <tt>_.memoize</tt>
    2145. 

  2145.         function, which can be used to speed up expensive repeated computations
    2146. 

  2146.         by caching the results.
    2147. 

  2147.       </p>
    2148. 

  2148. 

  2149.       <p>
    2150. 

  2150.         <b class="header">1.0.3</b><br />
    2151. 

  2151.         Patch that makes <tt>_.isEqual</tt> return <tt>false</tt> if any property
    2152. 

  2152.         of the compared object has a <tt>NaN</tt> value. Technically the correct
    2153. 

  2153.         thing to do, but of questionable semantics. Watch out for NaN comparisons.
    2154. 

  2154.       </p>
    2155. 

  2155. 

  2156.       <p>
    2157. 

  2157.         <b class="header">1.0.2</b><br />
    2158. 

  2158.         Fixes <tt>_.isArguments</tt> in recent versions of Opera, which have
    2159. 

  2159.         arguments objects as real Arrays.
    2160. 

  2160.       </p>
    2161. 

  2161. 

  2162.       <p>
    2163. 

  2163.         <b class="header">1.0.1</b><br />
    2164. 

  2164.         Bugfix for <tt>_.isEqual</tt>, when comparing two objects with the same
    2165. 

  2165.         number of undefined keys, but with different names.
    2166. 

  2166.       </p>
    2167. 

  2167. 

  2168.       <p>
    2169. 

  2169.         <b class="header">1.0.0</b><br />
    2170. 

  2170.         Things have been stable for many months now, so Underscore is now
    2171. 

  2171.         considered to be out of beta, at <b>1.0</b>. Improvements since <b>0.6</b>
    2172. 

  2172.         include <tt>_.isBoolean</tt>, and the ability to have <tt>_.extend</tt>
    2173. 

  2173.         take multiple source objects.
    2174. 

  2174.       </p>
    2175. 

  2175. 

  2176.       <p>
    2177. 

  2177.         <b class="header">0.6.0</b><br />
    2178. 

  2178.         Major release. Incorporates a number of
    2179. 

  2179.         <a href="http://github.com/ratbeard">Mile Frawley's</a> refactors for
    2180. 

  2180.         safer duck-typing on collection functions, and cleaner internals. A new
    2181. 

  2181.         <tt>_.mixin</tt> method that allows you to extend Underscore with utility
    2182. 

  2182.         functions of your own. Added <tt>_.times</tt>, which works the same as in
    2183. 

  2183.         Ruby or Prototype.js. Native support for ECMAScript 5's <tt>Array.isArray</tt>,
    2184. 

  2184.         and <tt>Object.keys</tt>.
    2185. 

  2185.       </p>
    2186. 

  2186. 

  2187.       <p>
    2188. 

  2188.         <b class="header">0.5.8</b><br />
    2189. 

  2189.         Fixed Underscore's collection functions to work on
    2190. 

  2190.         <a href="https://developer.mozilla.org/En/DOM/NodeList">NodeLists</a> and
    2191. 

  2191.         <a href="https://developer.mozilla.org/En/DOM/HTMLCollection">HTMLCollections</a>
    2192. 

  2192.         once more, thanks to
    2193. 

  2193.         <a href="http://github.com/jmtulloss">Justin Tulloss</a>.
    2194. 

  2194.       </p>
    2195. 

  2195. 

  2196.       <p>
    2197. 

  2197.         <b class="header">0.5.7</b><br />
    2198. 

  2198.         A safer implementation of <tt>_.isArguments</tt>, and a
    2199. 

  2199.         faster <tt>_.isNumber</tt>,<br />thanks to
    2200. 

  2200.         <a href="http://jedschmidt.com/">Jed Schmidt</a>.
    2201. 

  2201.       </p>
    2202. 

  2202. 

  2203.       <p>
    2204. 

  2204.         <b class="header">0.5.6</b><br />
    2205. 

  2205.         Customizable delimiters for <tt>_.template</tt>, contributed by
    2206. 

  2206.         <a href="http://github.com/iamnoah">Noah Sloan</a>.
    2207. 

  2207.       </p>
    2208. 

  2208. 

  2209.       <p>
    2210. 

  2210.         <b class="header">0.5.5</b><br />
    2211. 

  2211.         Fix for a bug in MobileSafari's OOP-wrapper, with the arguments object.
    2212. 

  2212.       </p>
    2213. 

  2213. 

  2214.       <p>
    2215. 

  2215.         <b class="header">0.5.4</b><br />
    2216. 

  2216.         Fix for multiple single quotes within a template string for
    2217. 

  2217.         <tt>_.template</tt>. See:
    2218. 

  2218.         <a href="http://www.west-wind.com/Weblog/posts/509108.aspx">Rick Strahl's blog post</a>.
    2219. 

  2219.       </p>
    2220. 

  2220. 

  2221.       <p>
    2222. 

  2222.         <b class="header">0.5.2</b><br />
    2223. 

  2223.         New implementations of <tt>isArray</tt>, <tt>isDate</tt>, <tt>isFunction</tt>,
    2224. 

  2224.         <tt>isNumber</tt>, <tt>isRegExp</tt>, and <tt>isString</tt>, thanks to
    2225. 

  2225.         a suggestion from
    2226. 

  2226.         <a href="http://www.broofa.com/">Robert Kieffer</a>.
    2227. 

  2227.         Instead of doing <tt>Object#toString</tt>
    2228. 

  2228.         comparisons, they now check for expected properties, which is less safe,
    2229. 

  2229.         but more than an order of magnitude faster. Most other Underscore
    2230. 

  2230.         functions saw minor speed improvements as a result.
    2231. 

  2231.         <a href="http://dolzhenko.org/">Evgeniy Dolzhenko</a>
    2232. 

  2232.         contributed <tt>_.tap</tt>,
    2233. 

  2233.         <a href="http://ruby-doc.org/core-1.9/classes/Object.html#M000191">similar to Ruby 1.9's</a>,
    2234. 

  2234.         which is handy for injecting side effects (like logging) into chained calls.
    2235. 

  2235.       </p>
    2236. 

  2236. 

  2237.       <p>
    2238. 

  2238.         <b class="header">0.5.1</b><br />
    2239. 

  2239.         Added an <tt>_.isArguments</tt> function. Lots of little safety checks
    2240. 

  2240.         and optimizations contributed by
    2241. 

  2241.         <a href="http://github.com/iamnoah/">Noah Sloan</a> and
    2242. 

  2242.         <a href="http://themoell.com/">Andri Möll</a>.
    2243. 

  2243.       </p>
    2244. 

  2244. 

  2245.       <p>
    2246. 

  2246.         <b class="header">0.5.0</b><br />
    2247. 

  2247.         <b>[API Changes]</b> <tt>_.bindAll</tt> now takes the context object as
    2248. 

  2248.         its first parameter. If no method names are passed, all of the context
    2249. 

  2249.         object's methods are bound to it, enabling chaining and easier binding.
    2250. 

  2250.         <tt>_.functions</tt> now takes a single argument and returns the names
    2251. 

  2251.         of its Function properties. Calling <tt>_.functions(_)</tt> will get you
    2252. 

  2252.         the previous behavior.
    2253. 

  2253.         Added <tt>_.isRegExp</tt> so that <tt>isEqual</tt> can now test for RegExp equality.
    2254. 

  2254.         All of the "is" functions have been shrunk down into a single definition.
    2255. 

  2255.         <a href="http://github.com/grayrest/">Karl Guertin</a> contributed patches.
    2256. 

  2256.       </p>
    2257. 

  2257. 

  2258.       <p>
    2259. 

  2259.         <b class="header">0.4.7</b><br />
    2260. 

  2260.         Added <tt>isDate</tt>, <tt>isNaN</tt>, and <tt>isNull</tt>, for completeness.
    2261. 

  2261.         Optimizations for <tt>isEqual</tt> when checking equality between Arrays
    2262. 

  2262.         or Dates. <tt>_.keys</tt> is now <small><i><b>25%&ndash;2X</b></i></small> faster (depending on your
    2263. 

  2263.         browser) which speeds up the functions that rely on it, such as <tt>_.each</tt>.
    2264. 

  2264.       </p>
    2265. 

  2265. 

  2266.       <p>
    2267. 

  2267.         <b class="header">0.4.6</b><br />
    2268. 

  2268.         Added the <tt>range</tt> function, a port of the
    2269. 

  2269.         <a href="http://docs.python.org/library/functions.html#range">Python
    2270. 

  2270.         function of the same name</a>, for generating flexibly-numbered lists
    2271. 

  2271.         of integers. Original patch contributed by
    2272. 

  2272.         <a href="http://github.com/kylichuku">Kirill Ishanov</a>.
    2273. 

  2273.       </p>
    2274. 

  2274. 

  2275.       <p>
    2276. 

  2276.         <b class="header">0.4.5</b><br />
    2277. 

  2277.         Added <tt>rest</tt> for Arrays and arguments objects, and aliased
    2278. 

  2278.         <tt>first</tt> as <tt>head</tt>, and <tt>rest</tt> as <tt>tail</tt>,
    2279. 

  2279.         thanks to <a href="http://github.com/lukesutton/">Luke Sutton</a>'s patches.
    2280. 

  2280.         Added tests ensuring that all Underscore Array functions also work on
    2281. 

  2281.         <i>arguments</i> objects.
    2282. 

  2282.       </p>
    2283. 

  2283. 

  2284.       <p>
    2285. 

  2285.         <b class="header">0.4.4</b><br />
    2286. 

  2286.         Added <tt>isString</tt>, and <tt>isNumber</tt>, for consistency. Fixed
    2287. 

  2287.         <tt>_.isEqual(NaN, NaN)</tt> to return <i>true</i> (which is debatable).
    2288. 

  2288.       </p>
    2289. 

  2289. 

  2290.       <p>
    2291. 

  2291.         <b class="header">0.4.3</b><br />
    2292. 

  2292.         Started using the native <tt>StopIteration</tt> object in browsers that support it.
    2293. 

  2293.         Fixed Underscore setup for CommonJS environments.
    2294. 

  2294.       </p>
    2295. 

  2295. 

  2296.       <p>
    2297. 

  2297.         <b class="header">0.4.2</b><br />
    2298. 

  2298.         Renamed the unwrapping function to <tt>value</tt>, for clarity.
    2299. 

  2299.       </p>
    2300. 

  2300. 

  2301.       <p>
    2302. 

  2302.         <b class="header">0.4.1</b><br />
    2303. 

  2303.         Chained Underscore objects now support the Array prototype methods, so
    2304. 

  2304.         that you can perform the full range of operations on a wrapped array
    2305. 

  2305.         without having to break your chain. Added a <tt>breakLoop</tt> method
    2306. 

  2306.         to <b>break</b> in the middle of any Underscore iteration. Added an
    2307. 

  2307.         <tt>isEmpty</tt> function that works on arrays and objects.
    2308. 

  2308.       </p>
    2309. 

  2309. 

  2310.       <p>
    2311. 

  2311.         <b class="header">0.4.0</b><br />
    2312. 

  2312.         All Underscore functions can now be called in an object-oriented style,
    2313. 

  2313.         like so: <tt>_([1, 2, 3]).map(...);</tt>. Original patch provided by
    2314. 

  2314.         <a href="http://macournoyer.com/">Marc-André Cournoyer</a>.
    2315. 

  2315.         Wrapped objects can be chained through multiple
    2316. 

  2316.         method invocations. A <a href="#object-functions"><tt>functions</tt></a> method
    2317. 

  2317.         was added, providing a sorted list of all the functions in Underscore.
    2318. 

  2318.       </p>
    2319. 

  2319. 

  2320.       <p>
    2321. 

  2321.         <b class="header">0.3.3</b><br />
    2322. 

  2322.         Added the JavaScript 1.8 function <tt>reduceRight</tt>. Aliased it
    2323. 

  2323.         as <tt>foldr</tt>, and aliased <tt>reduce</tt> as <tt>foldl</tt>.
    2324. 

  2324.       </p>
    2325. 

  2325. 

  2326.       <p>
    2327. 

  2327.         <b class="header">0.3.2</b><br />
    2328. 

  2328.         Now runs on stock <a href="http://www.mozilla.org/rhino/">Rhino</a>
    2329. 

  2329.         interpreters with: <tt>load("underscore.js")</tt>.
    2330. 

  2330.         Added <a href="#identity"><tt>identity</tt></a> as a utility function.
    2331. 

  2331.       </p>
    2332. 

  2332. 

  2333.       <p>
    2334. 

  2334.         <b class="header">0.3.1</b><br />
    2335. 

  2335.         All iterators are now passed in the original collection as their third
    2336. 

  2336.         argument, the same as JavaScript 1.6's <b>forEach</b>. Iterating over
    2337. 

  2337.         objects is now called with <tt>(value, key, collection)</tt>, for details
    2338. 

  2338.         see <a href="#each"><tt>_.each</tt></a>.
    2339. 

  2339.       </p>
    2340. 

  2340. 

  2341.       <p>
    2342. 

  2342.         <b class="header">0.3.0</b><br />
    2343. 

  2343.         Added <a href="http://github.com/dmitryBaranovskiy">Dmitry Baranovskiy</a>'s
    2344. 

  2344.         comprehensive optimizations, merged in
    2345. 

  2345.         <a href="http://github.com/kriskowal/">Kris Kowal</a>'s patches to make Underscore
    2346. 

  2346.         <a href="http://wiki.commonjs.org/wiki/CommonJS">CommonJS</a> and
    2347. 

  2347.         <a href="http://narwhaljs.org/">Narwhal</a> compliant.
    2348. 

  2348.       </p>
    2349. 

  2349. 

  2350.       <p>
    2351. 

  2351.         <b class="header">0.2.0</b><br />
    2352. 

  2352.         Added <tt>compose</tt> and <tt>lastIndexOf</tt>, renamed <tt>inject</tt> to
    2353. 

  2353.         <tt>reduce</tt>, added aliases for <tt>inject</tt>, <tt>filter</tt>,
    2354. 

  2354.         <tt>every</tt>, <tt>some</tt>, and <tt>forEach</tt>.
    2355. 

  2355.       </p>
    2356. 

  2356. 

  2357.       <p>
    2358. 

  2358.         <b class="header">0.1.1</b><br />
    2359. 

  2359.         Added <tt>noConflict</tt>, so that the "Underscore" object can be assigned to
    2360. 

  2360.         other variables.
    2361. 

  2361.       </p>
    2362. 

  2362. 

  2363.       <p>
    2364. 

  2364.         <b class="header">0.1.0</b><br />
    2365. 

  2365.         Initial release of Underscore.js.
    2366. 

  2366.       </p>
    2367. 

  2367. 

  2368.       <p>
    2369. 

  2369.         <a href="http://documentcloud.org/" title="A DocumentCloud Project" style="background:none;">
    2370. 

  2370.           <img src="http://jashkenas.s3.amazonaws.com/images/a_documentcloud_project.png" alt="A DocumentCloud Project" />
    2371. 

  2371.         </a>
    2372. 

  2372.       </p>
    2373. 

  2373. 

  2374.     </div>
    2375. 

  2375. 

  2376.   </div>
    2377. 

  2377. 

  2378.   <!-- Include Underscore, so you can play with it in the console. -->
    2379. 

  2379.   <script type="text/javascript" src="underscore.js"></script>
    2380. 

  2380. 

  2381. </body>
    2382. 

  2382. </html>
    2383. 

  2383.