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  1. <!DOCTYPE html>
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  3. <html>
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  4. <head>
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  5.   <title>underscore.coffee</title>
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  6.   <meta http-equiv="content-type" content="text/html; charset=UTF-8">
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  7.   <meta name="viewport" content="width=device-width, target-densitydpi=160dpi, initial-scale=1.0; maximum-scale=1.0; user-scalable=0;">
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  8.   <link rel="stylesheet" media="all" href="docco.css" />
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  9. </head>
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  10. <body>
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  11.   <div id="container">
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  12.     <div id="background"></div>
    13. 

  13.     
    14. 

  14.     <ul class="sections">
    15. 

  15.         
    16. 

  16.           <li id="title">
    17. 

  17.               <div class="annotation">
    18. 

  18.                   <h1>underscore.coffee</h1>
    19. 

  19.               </div>
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  20.           </li>
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  21.         
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  22.         
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  23.         
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  24.         <li id="section-1">
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  25.             <div class="annotation">
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  26.               
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  28.                 <a class="pilcrow" href="#section-1">&#182;</a>
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  29.               </div>
    30. 

  30.               <p><strong>Underscore.coffee
    31. 

  31. (c) 2011 Jeremy Ashkenas, DocumentCloud Inc.</strong>
    32. 

  32. Underscore is freely distributable under the terms of the
    33. 

  33. <a href="http://en.wikipedia.org/wiki/MIT_License">MIT license</a>.
    34. 

  34. Portions of Underscore are inspired by or borrowed from
    35. 

  35. <a href="http://prototypejs.org/api">Prototype.js</a>, Oliver Steele&#39;s
    36. 

  36. <a href="http://osteele.com">Functional</a>, and John Resig&#39;s
    37. 

  37. <a href="http://ejohn.org">Micro-Templating</a>.
    38. 

  38. For all details and documentation:
    39. 

  39. <a href="http://documentcloud.github.com/underscore/">http://documentcloud.github.com/underscore/</a></p>
    40. 

  40. <h2>Baseline setup</h2>
    41. 

  41. 

  42.             </div>
    43. 

  43.             
    44. 

  44.         </li>
    45. 

  45.         
    46. 

  46.         
    47. 

  47.         <li id="section-2">
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  48.             <div class="annotation">
    49. 

  49.               
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  50.               <div class="pilwrap ">
    51. 

  51.                 <a class="pilcrow" href="#section-2">&#182;</a>
    52. 

  52.               </div>
    53. 

  53.               <p>Establish the root object, <code>window</code> in the browser, or <code>global</code> on the server.</p>
    54. 

  54. 

  55.             </div>
    56. 

  56.             
    57. 

  57.             <div class="content"><div class='highlight'><pre>root = <span class="keyword">this</span></pre></div></div>
    58. 

  58.             
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  59.         </li>
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  60.         
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  61.         
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  62.         <li id="section-3">
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  63.             <div class="annotation">
    64. 

  64.               
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  65.               <div class="pilwrap ">
    66. 

  66.                 <a class="pilcrow" href="#section-3">&#182;</a>
    67. 

  67.               </div>
    68. 

  68.               <p>Save the previous value of the <code>_</code> variable.</p>
    69. 

  69. 

  70.             </div>
    71. 

  71.             
    72. 

  72.             <div class="content"><div class='highlight'><pre>previousUnderscore = root._</pre></div></div>
    73. 

  73.             
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  74.         </li>
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  75.         
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  76.         
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  77.         <li id="section-4">
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  78.             <div class="annotation">
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  79.               
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  80.               <div class="pilwrap ">
    81. 

  81.                 <a class="pilcrow" href="#section-4">&#182;</a>
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  82.               </div>
    83. 

  83.               <p>Establish the object that gets thrown to break out of a loop iteration.
    84. 

  84. <code>StopIteration</code> is SOP on Mozilla.</p>
    85. 

  85. 

  86.             </div>
    87. 

  87.             
    88. 

  88.             <div class="content"><div class='highlight'><pre>breaker = <span class="keyword">if</span> <span class="keyword">typeof</span>(StopIteration) <span class="keyword">is</span> <span class="string">'undefined'</span> <span class="keyword">then</span> <span class="string">'__break__'</span> <span class="keyword">else</span> StopIteration</pre></div></div>
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  93.         <li id="section-5">
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  94.             <div class="annotation">
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  95.               
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  96.               <div class="pilwrap ">
    97. 

  97.                 <a class="pilcrow" href="#section-5">&#182;</a>
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  98.               </div>
    99. 

  99.               <p>Helper function to escape <strong>RegExp</strong> contents, because JS doesn&#39;t have one.</p>
    100. 

  100. 

  101.             </div>
    102. 

  102.             
    103. 

  103.             <div class="content"><div class='highlight'><pre><span class="function"><span class="title">escapeRegExp</span></span> = (string) -&gt; string.replace(<span class="regexp">/([.*+?^${}()|[\]\/\\])/g</span>, <span class="string">'\\$1'</span>)</pre></div></div>
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  104.             
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  105.         </li>
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  106.         
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  107.         
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  108.         <li id="section-6">
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  109.             <div class="annotation">
    110. 

  110.               
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  111.               <div class="pilwrap ">
    112. 

  112.                 <a class="pilcrow" href="#section-6">&#182;</a>
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  113.               </div>
    114. 

  114.               <p>Save bytes in the minified (but not gzipped) version:</p>
    115. 

  115. 

  116.             </div>
    117. 

  117.             
    118. 

  118.             <div class="content"><div class='highlight'><pre>ArrayProto           = Array.prototype
    119. 

  119. ObjProto             = Object.prototype</pre></div></div>
    120. 

  120.             
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  121.         </li>
    122. 

  122.         
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  123.         
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  124.         <li id="section-7">
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  125.             <div class="annotation">
    126. 

  126.               
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  127.               <div class="pilwrap ">
    128. 

  128.                 <a class="pilcrow" href="#section-7">&#182;</a>
    129. 

  129.               </div>
    130. 

  130.               <p>Create quick reference variables for speed access to core prototypes.</p>
    131. 

  131. 

  132.             </div>
    133. 

  133.             
    134. 

  134.             <div class="content"><div class='highlight'><pre>slice                = ArrayProto.slice
    135. 

  135. unshift              = ArrayProto.unshift
    136. 

  136. toString             = ObjProto.toString
    137. 

  137. hasOwnProperty       = ObjProto.hasOwnProperty
    138. 

  138. propertyIsEnumerable = ObjProto.propertyIsEnumerable</pre></div></div>
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  139.             
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  140.         </li>
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  141.         
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  142.         
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  143.         <li id="section-8">
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  144.             <div class="annotation">
    145. 

  145.               
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  146.               <div class="pilwrap ">
    147. 

  147.                 <a class="pilcrow" href="#section-8">&#182;</a>
    148. 

  148.               </div>
    149. 

  149.               <p>All <strong>ECMA5</strong> native implementations we hope to use are declared here.</p>
    150. 

  150. 

  151.             </div>
    152. 

  152.             
    153. 

  153.             <div class="content"><div class='highlight'><pre>nativeForEach        = ArrayProto.forEach
    154. 

  154. nativeMap            = ArrayProto.map
    155. 

  155. nativeReduce         = ArrayProto.reduce
    156. 

  156. nativeReduceRight    = ArrayProto.reduceRight
    157. 

  157. nativeFilter         = ArrayProto.filter
    158. 

  158. nativeEvery          = ArrayProto.every
    159. 

  159. nativeSome           = ArrayProto.some
    160. 

  160. nativeIndexOf        = ArrayProto.indexOf
    161. 

  161. nativeLastIndexOf    = ArrayProto.lastIndexOf
    162. 

  162. nativeIsArray        = Array.isArray
    163. 

  163. nativeKeys           = Object.keys</pre></div></div>
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  164.             
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  165.         </li>
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  166.         
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  167.         
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  168.         <li id="section-9">
    169. 

  169.             <div class="annotation">
    170. 

  170.               
    171. 

  171.               <div class="pilwrap ">
    172. 

  172.                 <a class="pilcrow" href="#section-9">&#182;</a>
    173. 

  173.               </div>
    174. 

  174.               <p>Create a safe reference to the Underscore object for use below.</p>
    175. 

  175. 

  176.             </div>
    177. 

  177.             
    178. 

  178.             <div class="content"><div class='highlight'><pre><span class="function"><span class="title">_</span></span> = (obj) -&gt; <span class="keyword">new</span> wrapper(obj)</pre></div></div>
    179. 

  179.             
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  180.         </li>
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  181.         
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  182.         
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  183.         <li id="section-10">
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  184.             <div class="annotation">
    185. 

  185.               
    186. 

  186.               <div class="pilwrap ">
    187. 

  187.                 <a class="pilcrow" href="#section-10">&#182;</a>
    188. 

  188.               </div>
    189. 

  189.               <p>Export the Underscore object for <strong>CommonJS</strong>.</p>
    190. 

  190. 

  191.             </div>
    192. 

  192.             
    193. 

  193.             <div class="content"><div class='highlight'><pre><span class="keyword">if</span> <span class="keyword">typeof</span>(exports) != <span class="string">'undefined'</span> <span class="keyword">then</span> exports._ = _</pre></div></div>
    194. 

  194.             
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  195.         </li>
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  196.         
    197. 

  197.         
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  198.         <li id="section-11">
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  199.             <div class="annotation">
    200. 

  200.               
    201. 

  201.               <div class="pilwrap ">
    202. 

  202.                 <a class="pilcrow" href="#section-11">&#182;</a>
    203. 

  203.               </div>
    204. 

  204.               <p>Export Underscore to global scope.</p>
    205. 

  205. 

  206.             </div>
    207. 

  207.             
    208. 

  208.             <div class="content"><div class='highlight'><pre>root._ = _</pre></div></div>
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  209.             
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  210.         </li>
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  213.         <li id="section-12">
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  214.             <div class="annotation">
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  215.               
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  216.               <div class="pilwrap ">
    217. 

  217.                 <a class="pilcrow" href="#section-12">&#182;</a>
    218. 

  218.               </div>
    219. 

  219.               <p>Current version.</p>
    220. 

  220. 

  221.             </div>
    222. 

  222.             
    223. 

  223.             <div class="content"><div class='highlight'><pre>_.VERSION = <span class="string">'1.1.0'</span></pre></div></div>
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  224.             
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  225.         </li>
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  229.             <div class="annotation">
    230. 

  230.               
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  231.               <div class="pilwrap for-h2">
    232. 

  232.                 <a class="pilcrow" href="#section-13">&#182;</a>
    233. 

  233.               </div>
    234. 

  234.               <h2>Collection Functions</h2>
    235. 

  235. 

  236.             </div>
    237. 

  237.             
    238. 

  238.         </li>
    239. 

  239.         
    240. 

  240.         
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  241.         <li id="section-14">
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  242.             <div class="annotation">
    243. 

  243.               
    244. 

  244.               <div class="pilwrap ">
    245. 

  245.                 <a class="pilcrow" href="#section-14">&#182;</a>
    246. 

  246.               </div>
    247. 

  247.               <p>The cornerstone, an <strong>each</strong> implementation.
    248. 

  248. Handles objects implementing <strong>forEach</strong>, arrays, and raw objects.</p>
    249. 

  249. 

  250.             </div>
    251. 

  251.             
    252. 

  252.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">each</span></span> = (obj, iterator, context) -&gt;
    253. 

  253.   <span class="keyword">try</span>
    254. 

  254.     <span class="keyword">if</span> nativeForEach <span class="keyword">and</span> obj.forEach <span class="keyword">is</span> nativeForEach
    255. 

  255.       obj.forEach iterator, context
    256. 

  256.     <span class="keyword">else</span> <span class="keyword">if</span> _.isNumber obj.length
    257. 

  257.       iterator.call context, obj[i], i, obj <span class="keyword">for</span> i <span class="keyword">in</span> [<span class="number">0.</span>..obj.length]
    258. 

  258.     <span class="keyword">else</span>
    259. 

  259.       iterator.call context, val, key, obj  <span class="keyword">for</span> own key, val <span class="keyword">of</span> obj
    260. 

  260.   <span class="keyword">catch</span> e
    261. 

  261.     <span class="keyword">throw</span> e <span class="keyword">if</span> e <span class="keyword">isnt</span> breaker
    262. 

  262.   obj</pre></div></div>
    263. 

  263.             
    264. 

  264.         </li>
    265. 

  265.         
    266. 

  266.         
    267. 

  267.         <li id="section-15">
    268. 

  268.             <div class="annotation">
    269. 

  269.               
    270. 

  270.               <div class="pilwrap ">
    271. 

  271.                 <a class="pilcrow" href="#section-15">&#182;</a>
    272. 

  272.               </div>
    273. 

  273.               <p>Return the results of applying the iterator to each element. Use JavaScript
    274. 

  274. 1.6&#39;s version of <strong>map</strong>, if possible.</p>
    275. 

  275. 

  276.             </div>
    277. 

  277.             
    278. 

  278.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">map</span></span> = (obj, iterator, context) -&gt;
    279. 

  279.   <span class="keyword">return</span> obj.map(iterator, context) <span class="keyword">if</span> nativeMap <span class="keyword">and</span> obj.map <span class="keyword">is</span> nativeMap
    280. 

  280.   results = []
    281. 

  281.   _.each obj, (value, index, list) -&gt;
    282. 

  282.     results.push iterator.call context, value, index, list
    283. 

  283.   results</pre></div></div>
    284. 

  284.             
    285. 

  285.         </li>
    286. 

  286.         
    287. 

  287.         
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  288.         <li id="section-16">
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  289.             <div class="annotation">
    290. 

  290.               
    291. 

  291.               <div class="pilwrap ">
    292. 

  292.                 <a class="pilcrow" href="#section-16">&#182;</a>
    293. 

  293.               </div>
    294. 

  294.               <p><strong>Reduce</strong> builds up a single result from a list of values. Also known as
    295. 

  295. <strong>inject</strong>, or <strong>foldl</strong>. Uses JavaScript 1.8&#39;s version of <strong>reduce</strong>, if possible.</p>
    296. 

  296. 

  297.             </div>
    298. 

  298.             
    299. 

  299.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">reduce</span></span> = (obj, iterator, memo, context) -&gt;
    300. 

  300.   <span class="keyword">if</span> nativeReduce <span class="keyword">and</span> obj.reduce <span class="keyword">is</span> nativeReduce
    301. 

  301.     iterator = _.bind iterator, context <span class="keyword">if</span> context
    302. 

  302.     <span class="keyword">return</span> obj.reduce iterator, memo
    303. 

  303.   _.each obj, (value, index, list) -&gt;
    304. 

  304.     memo = iterator.call context, memo, value, index, list
    305. 

  305.   memo</pre></div></div>
    306. 

  306.             
    307. 

  307.         </li>
    308. 

  308.         
    309. 

  309.         
    310. 

  310.         <li id="section-17">
    311. 

  311.             <div class="annotation">
    312. 

  312.               
    313. 

  313.               <div class="pilwrap ">
    314. 

  314.                 <a class="pilcrow" href="#section-17">&#182;</a>
    315. 

  315.               </div>
    316. 

  316.               <p>The right-associative version of <strong>reduce</strong>, also known as <strong>foldr</strong>. Uses
    317. 

  317. JavaScript 1.8&#39;s version of <strong>reduceRight</strong>, if available.</p>
    318. 

  318. 

  319.             </div>
    320. 

  320.             
    321. 

  321.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">reduceRight</span></span> = (obj, iterator, memo, context) -&gt;
    322. 

  322.   <span class="keyword">if</span> nativeReduceRight <span class="keyword">and</span> obj.reduceRight <span class="keyword">is</span> nativeReduceRight
    323. 

  323.     iterator = _.bind iterator, context <span class="keyword">if</span> context
    324. 

  324.     <span class="keyword">return</span> obj.reduceRight iterator, memo
    325. 

  325.   reversed = _.clone(_.toArray(obj)).reverse()
    326. 

  326.   _.reduce reversed, iterator, memo, context</pre></div></div>
    327. 

  327.             
    328. 

  328.         </li>
    329. 

  329.         
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  330.         
    331. 

  331.         <li id="section-18">
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  332.             <div class="annotation">
    333. 

  333.               
    334. 

  334.               <div class="pilwrap ">
    335. 

  335.                 <a class="pilcrow" href="#section-18">&#182;</a>
    336. 

  336.               </div>
    337. 

  337.               <p>Return the first value which passes a truth test.</p>
    338. 

  338. 

  339.             </div>
    340. 

  340.             
    341. 

  341.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">detect</span></span> = (obj, iterator, context) -&gt;
    342. 

  342.   result = <span class="literal">null</span>
    343. 

  343.   _.each obj, (value, index, list) -&gt;
    344. 

  344.     <span class="keyword">if</span> iterator.call context, value, index, list
    345. 

  345.       result = value
    346. 

  346.       _.breakLoop()
    347. 

  347.   result</pre></div></div>
    348. 

  348.             
    349. 

  349.         </li>
    350. 

  350.         
    351. 

  351.         
    352. 

  352.         <li id="section-19">
    353. 

  353.             <div class="annotation">
    354. 

  354.               
    355. 

  355.               <div class="pilwrap ">
    356. 

  356.                 <a class="pilcrow" href="#section-19">&#182;</a>
    357. 

  357.               </div>
    358. 

  358.               <p>Return all the elements that pass a truth test. Use JavaScript 1.6&#39;s
    359. 

  359. <strong>filter</strong>, if it exists.</p>
    360. 

  360. 

  361.             </div>
    362. 

  362.             
    363. 

  363.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">filter</span></span> = (obj, iterator, context) -&gt;
    364. 

  364.   <span class="keyword">return</span> obj.filter iterator, context <span class="keyword">if</span> nativeFilter <span class="keyword">and</span> obj.filter <span class="keyword">is</span> nativeFilter
    365. 

  365.   results = []
    366. 

  366.   _.each obj, (value, index, list) -&gt;
    367. 

  367.     results.push value <span class="keyword">if</span> iterator.call context, value, index, list
    368. 

  368.   results</pre></div></div>
    369. 

  369.             
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  370.         </li>
    371. 

  371.         
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  372.         
    373. 

  373.         <li id="section-20">
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  374.             <div class="annotation">
    375. 

  375.               
    376. 

  376.               <div class="pilwrap ">
    377. 

  377.                 <a class="pilcrow" href="#section-20">&#182;</a>
    378. 

  378.               </div>
    379. 

  379.               <p>Return all the elements for which a truth test fails.</p>
    380. 

  380. 

  381.             </div>
    382. 

  382.             
    383. 

  383.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">reject</span></span> = (obj, iterator, context) -&gt;
    384. 

  384.   results = []
    385. 

  385.   _.each obj, (value, index, list) -&gt;
    386. 

  386.     results.push value <span class="keyword">if</span> <span class="keyword">not</span> iterator.call context, value, index, list
    387. 

  387.   results</pre></div></div>
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  388.             
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  389.         </li>
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  390.         
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  391.         
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  392.         <li id="section-21">
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  393.             <div class="annotation">
    394. 

  394.               
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  395.               <div class="pilwrap ">
    396. 

  396.                 <a class="pilcrow" href="#section-21">&#182;</a>
    397. 

  397.               </div>
    398. 

  398.               <p>Determine whether all of the elements match a truth test. Delegate to
    399. 

  399. JavaScript 1.6&#39;s <strong>every</strong>, if it is present.</p>
    400. 

  400. 

  401.             </div>
    402. 

  402.             
    403. 

  403.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">every</span></span> = (obj, iterator, context) -&gt;
    404. 

  404.   iterator ||= _.identity
    405. 

  405.   <span class="keyword">return</span> obj.every iterator, context <span class="keyword">if</span> nativeEvery <span class="keyword">and</span> obj.every <span class="keyword">is</span> nativeEvery
    406. 

  406.   result = <span class="literal">true</span>
    407. 

  407.   _.each obj, (value, index, list) -&gt;
    408. 

  408.     _.breakLoop() <span class="keyword">unless</span> (result = result <span class="keyword">and</span> iterator.call(context, value, index, list))
    409. 

  409.   result</pre></div></div>
    410. 

  410.             
    411. 

  411.         </li>
    412. 

  412.         
    413. 

  413.         
    414. 

  414.         <li id="section-22">
    415. 

  415.             <div class="annotation">
    416. 

  416.               
    417. 

  417.               <div class="pilwrap ">
    418. 

  418.                 <a class="pilcrow" href="#section-22">&#182;</a>
    419. 

  419.               </div>
    420. 

  420.               <p>Determine if at least one element in the object matches a truth test. Use
    421. 

  421. JavaScript 1.6&#39;s <strong>some</strong>, if it exists.</p>
    422. 

  422. 

  423.             </div>
    424. 

  424.             
    425. 

  425.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">some</span></span> = (obj, iterator, context) -&gt;
    426. 

  426.   iterator ||= _.identity
    427. 

  427.   <span class="keyword">return</span> obj.some iterator, context <span class="keyword">if</span> nativeSome <span class="keyword">and</span> obj.some <span class="keyword">is</span> nativeSome
    428. 

  428.   result = <span class="literal">false</span>
    429. 

  429.   _.each obj, (value, index, list) -&gt;
    430. 

  430.     _.breakLoop() <span class="keyword">if</span> (result = iterator.call(context, value, index, list))
    431. 

  431.   result</pre></div></div>
    432. 

  432.             
    433. 

  433.         </li>
    434. 

  434.         
    435. 

  435.         
    436. 

  436.         <li id="section-23">
    437. 

  437.             <div class="annotation">
    438. 

  438.               
    439. 

  439.               <div class="pilwrap ">
    440. 

  440.                 <a class="pilcrow" href="#section-23">&#182;</a>
    441. 

  441.               </div>
    442. 

  442.               <p>Determine if a given value is included in the array or object,
    443. 

  443. based on <code>===</code>.</p>
    444. 

  444. 

  445.             </div>
    446. 

  446.             
    447. 

  447.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">include</span></span> = (obj, target) -&gt;
    448. 

  448.   <span class="keyword">return</span> _.indexOf(obj, target) <span class="keyword">isnt</span> -<span class="number">1</span> <span class="keyword">if</span> nativeIndexOf <span class="keyword">and</span> obj.indexOf <span class="keyword">is</span> nativeIndexOf
    449. 

  449.   <span class="keyword">return</span> <span class="literal">true</span> <span class="keyword">for</span> own key, val <span class="keyword">of</span> obj <span class="keyword">when</span> val <span class="keyword">is</span> target
    450. 

  450.   <span class="literal">false</span></pre></div></div>
    451. 

  451.             
    452. 

  452.         </li>
    453. 

  453.         
    454. 

  454.         
    455. 

  455.         <li id="section-24">
    456. 

  456.             <div class="annotation">
    457. 

  457.               
    458. 

  458.               <div class="pilwrap ">
    459. 

  459.                 <a class="pilcrow" href="#section-24">&#182;</a>
    460. 

  460.               </div>
    461. 

  461.               <p>Invoke a method with arguments on every item in a collection.</p>
    462. 

  462. 

  463.             </div>
    464. 

  464.             
    465. 

  465.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">invoke</span></span> = (obj, method) -&gt;
    466. 

  466.   args = _.rest arguments, <span class="number">2</span>
    467. 

  467.   (<span class="keyword">if</span> method <span class="keyword">then</span> val[method] <span class="keyword">else</span> val).apply(val, args) <span class="keyword">for</span> val <span class="keyword">in</span> obj</pre></div></div>
    468. 

  468.             
    469. 

  469.         </li>
    470. 

  470.         
    471. 

  471.         
    472. 

  472.         <li id="section-25">
    473. 

  473.             <div class="annotation">
    474. 

  474.               
    475. 

  475.               <div class="pilwrap ">
    476. 

  476.                 <a class="pilcrow" href="#section-25">&#182;</a>
    477. 

  477.               </div>
    478. 

  478.               <p>Convenience version of a common use case of <strong>map</strong>: fetching a property.</p>
    479. 

  479. 

  480.             </div>
    481. 

  481.             
    482. 

  482.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">pluck</span></span> = (obj, key) -&gt;
    483. 

  483.   _.map(obj, (val) -&gt; val[key])</pre></div></div>
    484. 

  484.             
    485. 

  485.         </li>
    486. 

  486.         
    487. 

  487.         
    488. 

  488.         <li id="section-26">
    489. 

  489.             <div class="annotation">
    490. 

  490.               
    491. 

  491.               <div class="pilwrap ">
    492. 

  492.                 <a class="pilcrow" href="#section-26">&#182;</a>
    493. 

  493.               </div>
    494. 

  494.               <p>Return the maximum item or (item-based computation).</p>
    495. 

  495. 

  496.             </div>
    497. 

  497.             
    498. 

  498.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">max</span></span> = (obj, iterator, context) -&gt;
    499. 

  499.   <span class="keyword">return</span> Math.max.apply(Math, obj) <span class="keyword">if</span> <span class="keyword">not</span> iterator <span class="keyword">and</span> _.isArray(obj)
    500. 

  500.   result = computed: -Infinity
    501. 

  501.   _.each obj, (value, index, list) -&gt;
    502. 

  502.     computed = <span class="keyword">if</span> iterator <span class="keyword">then</span> iterator.call(context, value, index, list) <span class="keyword">else</span> value
    503. 

  503.     computed &gt;= result.computed <span class="keyword">and</span> (result = {value: value, computed: computed})
    504. 

  504.   result.value</pre></div></div>
    505. 

  505.             
    506. 

  506.         </li>
    507. 

  507.         
    508. 

  508.         
    509. 

  509.         <li id="section-27">
    510. 

  510.             <div class="annotation">
    511. 

  511.               
    512. 

  512.               <div class="pilwrap ">
    513. 

  513.                 <a class="pilcrow" href="#section-27">&#182;</a>
    514. 

  514.               </div>
    515. 

  515.               <p>Return the minimum element (or element-based computation).</p>
    516. 

  516. 

  517.             </div>
    518. 

  518.             
    519. 

  519.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">min</span></span> = (obj, iterator, context) -&gt;
    520. 

  520.   <span class="keyword">return</span> Math.min.apply(Math, obj) <span class="keyword">if</span> <span class="keyword">not</span> iterator <span class="keyword">and</span> _.isArray(obj)
    521. 

  521.   result = computed: Infinity
    522. 

  522.   _.each obj, (value, index, list) -&gt;
    523. 

  523.     computed = <span class="keyword">if</span> iterator <span class="keyword">then</span> iterator.call(context, value, index, list) <span class="keyword">else</span> value
    524. 

  524.     computed &lt; result.computed <span class="keyword">and</span> (result = {value: value, computed: computed})
    525. 

  525.   result.value</pre></div></div>
    526. 

  526.             
    527. 

  527.         </li>
    528. 

  528.         
    529. 

  529.         
    530. 

  530.         <li id="section-28">
    531. 

  531.             <div class="annotation">
    532. 

  532.               
    533. 

  533.               <div class="pilwrap ">
    534. 

  534.                 <a class="pilcrow" href="#section-28">&#182;</a>
    535. 

  535.               </div>
    536. 

  536.               <p>Sort the object&#39;s values by a criterion produced by an iterator.</p>
    537. 

  537. 

  538.             </div>
    539. 

  539.             
    540. 

  540.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">sortBy</span></span> = (obj, iterator, context) -&gt;
    541. 

  541.   _.pluck(((_.map obj, (value, index, list) -&gt;
    542. 

  542.     {value: value, criteria: iterator.call(context, value, index, list)}
    543. 

  543.   ).sort((left, right) -&gt;
    544. 

  544.     a = left.criteria; b = right.criteria
    545. 

  545.     <span class="keyword">if</span> a &lt; b <span class="keyword">then</span> -<span class="number">1</span> <span class="keyword">else</span> <span class="keyword">if</span> a &gt; b <span class="keyword">then</span> <span class="number">1</span> <span class="keyword">else</span> <span class="number">0</span>
    546. 

  546.   )), <span class="string">'value'</span>)</pre></div></div>
    547. 

  547.             
    548. 

  548.         </li>
    549. 

  549.         
    550. 

  550.         
    551. 

  551.         <li id="section-29">
    552. 

  552.             <div class="annotation">
    553. 

  553.               
    554. 

  554.               <div class="pilwrap ">
    555. 

  555.                 <a class="pilcrow" href="#section-29">&#182;</a>
    556. 

  556.               </div>
    557. 

  557.               <p>Use a comparator function to figure out at what index an object should
    558. 

  558. be inserted so as to maintain order. Uses binary search.</p>
    559. 

  559. 

  560.             </div>
    561. 

  561.             
    562. 

  562.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">sortedIndex</span></span> = (array, obj, iterator) -&gt;
    563. 

  563.   iterator ||= _.identity
    564. 

  564.   low =  <span class="number">0</span>
    565. 

  565.   high = array.length
    566. 

  566.   <span class="keyword">while</span> low &lt; high
    567. 

  567.     mid = (low + high) &gt;&gt; <span class="number">1</span>
    568. 

  568.     <span class="keyword">if</span> iterator(array[mid]) &lt; iterator(obj) <span class="keyword">then</span> low = mid + <span class="number">1</span> <span class="keyword">else</span> high = mid
    569. 

  569.   low</pre></div></div>
    570. 

  570.             
    571. 

  571.         </li>
    572. 

  572.         
    573. 

  573.         
    574. 

  574.         <li id="section-30">
    575. 

  575.             <div class="annotation">
    576. 

  576.               
    577. 

  577.               <div class="pilwrap ">
    578. 

  578.                 <a class="pilcrow" href="#section-30">&#182;</a>
    579. 

  579.               </div>
    580. 

  580.               <p>Convert anything iterable into a real, live array.</p>
    581. 

  581. 

  582.             </div>
    583. 

  583.             
    584. 

  584.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">toArray</span></span> = (iterable) -&gt;
    585. 

  585.   <span class="keyword">return</span> []                   <span class="keyword">if</span> (!iterable)
    586. 

  586.   <span class="keyword">return</span> iterable.toArray()   <span class="keyword">if</span> (iterable.toArray)
    587. 

  587.   <span class="keyword">return</span> iterable             <span class="keyword">if</span> (_.isArray(iterable))
    588. 

  588.   <span class="keyword">return</span> slice.call(iterable) <span class="keyword">if</span> (_.isArguments(iterable))
    589. 

  589.   _.values(iterable)</pre></div></div>
    590. 

  590.             
    591. 

  591.         </li>
    592. 

  592.         
    593. 

  593.         
    594. 

  594.         <li id="section-31">
    595. 

  595.             <div class="annotation">
    596. 

  596.               
    597. 

  597.               <div class="pilwrap ">
    598. 

  598.                 <a class="pilcrow" href="#section-31">&#182;</a>
    599. 

  599.               </div>
    600. 

  600.               <p>Return the number of elements in an object.</p>
    601. 

  601. 

  602.             </div>
    603. 

  603.             
    604. 

  604.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">size</span></span> = (obj) -&gt; _.toArray(obj).length</pre></div></div>
    605. 

  605.             
    606. 

  606.         </li>
    607. 

  607.         
    608. 

  608.         
    609. 

  609.         <li id="section-32">
    610. 

  610.             <div class="annotation">
    611. 

  611.               
    612. 

  612.               <div class="pilwrap for-h2">
    613. 

  613.                 <a class="pilcrow" href="#section-32">&#182;</a>
    614. 

  614.               </div>
    615. 

  615.               <h2>Array Functions</h2>
    616. 

  616. 

  617.             </div>
    618. 

  618.             
    619. 

  619.         </li>
    620. 

  620.         
    621. 

  621.         
    622. 

  622.         <li id="section-33">
    623. 

  623.             <div class="annotation">
    624. 

  624.               
    625. 

  625.               <div class="pilwrap ">
    626. 

  626.                 <a class="pilcrow" href="#section-33">&#182;</a>
    627. 

  627.               </div>
    628. 

  628.               <p>Get the first element of an array. Passing <code>n</code> will return the first N
    629. 

  629. values in the array. Aliased as <strong>head</strong>. The <code>guard</code> check allows it to work
    630. 

  630. with <strong>map</strong>.</p>
    631. 

  631. 

  632.             </div>
    633. 

  633.             
    634. 

  634.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">first</span></span> = (array, n, guard) -&gt;
    635. 

  635.   <span class="keyword">if</span> n <span class="keyword">and</span> <span class="keyword">not</span> guard <span class="keyword">then</span> slice.call(array, <span class="number">0</span>, n) <span class="keyword">else</span> array[<span class="number">0</span>]</pre></div></div>
    636. 

  636.             
    637. 

  637.         </li>
    638. 

  638.         
    639. 

  639.         
    640. 

  640.         <li id="section-34">
    641. 

  641.             <div class="annotation">
    642. 

  642.               
    643. 

  643.               <div class="pilwrap ">
    644. 

  644.                 <a class="pilcrow" href="#section-34">&#182;</a>
    645. 

  645.               </div>
    646. 

  646.               <p>Returns everything but the first entry of the array. Aliased as <strong>tail</strong>.
    647. 

  647. Especially useful on the arguments object. Passing an <code>index</code> will return
    648. 

  648. the rest of the values in the array from that index onward. The <code>guard</code>
    649. 

  649. check allows it to work with <strong>map</strong>.</p>
    650. 

  650. 

  651.             </div>
    652. 

  652.             
    653. 

  653.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">rest</span></span> = (array, index, guard) -&gt;
    654. 

  654.   slice.call(array, <span class="keyword">if</span> _.isUndefined(index) <span class="keyword">or</span> guard <span class="keyword">then</span> <span class="number">1</span> <span class="keyword">else</span> index)</pre></div></div>
    655. 

  655.             
    656. 

  656.         </li>
    657. 

  657.         
    658. 

  658.         
    659. 

  659.         <li id="section-35">
    660. 

  660.             <div class="annotation">
    661. 

  661.               
    662. 

  662.               <div class="pilwrap ">
    663. 

  663.                 <a class="pilcrow" href="#section-35">&#182;</a>
    664. 

  664.               </div>
    665. 

  665.               <p>Get the last element of an array.</p>
    666. 

  666. 

  667.             </div>
    668. 

  668.             
    669. 

  669.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">last</span></span> = (array) -&gt; array[array.length - <span class="number">1</span>]</pre></div></div>
    670. 

  670.             
    671. 

  671.         </li>
    672. 

  672.         
    673. 

  673.         
    674. 

  674.         <li id="section-36">
    675. 

  675.             <div class="annotation">
    676. 

  676.               
    677. 

  677.               <div class="pilwrap ">
    678. 

  678.                 <a class="pilcrow" href="#section-36">&#182;</a>
    679. 

  679.               </div>
    680. 

  680.               <p>Trim out all falsy values from an array.</p>
    681. 

  681. 

  682.             </div>
    683. 

  683.             
    684. 

  684.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">compact</span></span> = (array) -&gt; item <span class="keyword">for</span> item <span class="keyword">in</span> array <span class="keyword">when</span> item</pre></div></div>
    685. 

  685.             
    686. 

  686.         </li>
    687. 

  687.         
    688. 

  688.         
    689. 

  689.         <li id="section-37">
    690. 

  690.             <div class="annotation">
    691. 

  691.               
    692. 

  692.               <div class="pilwrap ">
    693. 

  693.                 <a class="pilcrow" href="#section-37">&#182;</a>
    694. 

  694.               </div>
    695. 

  695.               <p>Return a completely flattened version of an array.</p>
    696. 

  696. 

  697.             </div>
    698. 

  698.             
    699. 

  699.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">flatten</span></span> = (array) -&gt;
    700. 

  700.   _.reduce array, (memo, value) -&gt;
    701. 

  701.     <span class="keyword">return</span> memo.concat(_.flatten(value)) <span class="keyword">if</span> _.isArray value
    702. 

  702.     memo.push value
    703. 

  703.     memo
    704. 

  704.   , []</pre></div></div>
    705. 

  705.             
    706. 

  706.         </li>
    707. 

  707.         
    708. 

  708.         
    709. 

  709.         <li id="section-38">
    710. 

  710.             <div class="annotation">
    711. 

  711.               
    712. 

  712.               <div class="pilwrap ">
    713. 

  713.                 <a class="pilcrow" href="#section-38">&#182;</a>
    714. 

  714.               </div>
    715. 

  715.               <p>Return a version of the array that does not contain the specified value(s).</p>
    716. 

  716. 

  717.             </div>
    718. 

  718.             
    719. 

  719.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">without</span></span> = (array) -&gt;
    720. 

  720.   values = _.rest arguments
    721. 

  721.   val <span class="keyword">for</span> val <span class="keyword">in</span> _.toArray(array) <span class="keyword">when</span> <span class="keyword">not</span> _.include values, val</pre></div></div>
    722. 

  722.             
    723. 

  723.         </li>
    724. 

  724.         
    725. 

  725.         
    726. 

  726.         <li id="section-39">
    727. 

  727.             <div class="annotation">
    728. 

  728.               
    729. 

  729.               <div class="pilwrap ">
    730. 

  730.                 <a class="pilcrow" href="#section-39">&#182;</a>
    731. 

  731.               </div>
    732. 

  732.               <p>Produce a duplicate-free version of the array. If the array has already
    733. 

  733. been sorted, you have the option of using a faster algorithm.</p>
    734. 

  734. 

  735.             </div>
    736. 

  736.             
    737. 

  737.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">uniq</span></span> = (array, isSorted) -&gt;
    738. 

  738.   memo = []
    739. 

  739.   <span class="keyword">for</span> el, i <span class="keyword">in</span> _.toArray array
    740. 

  740.     memo.push el <span class="keyword">if</span> i <span class="keyword">is</span> <span class="number">0</span> || (<span class="keyword">if</span> isSorted <span class="keyword">is</span> <span class="literal">true</span> <span class="keyword">then</span> _.last(memo) <span class="keyword">isnt</span> el <span class="keyword">else</span> <span class="keyword">not</span> _.include(memo, el))
    741. 

  741.   memo</pre></div></div>
    742. 

  742.             
    743. 

  743.         </li>
    744. 

  744.         
    745. 

  745.         
    746. 

  746.         <li id="section-40">
    747. 

  747.             <div class="annotation">
    748. 

  748.               
    749. 

  749.               <div class="pilwrap ">
    750. 

  750.                 <a class="pilcrow" href="#section-40">&#182;</a>
    751. 

  751.               </div>
    752. 

  752.               <p>Produce an array that contains every item shared between all the
    753. 

  753. passed-in arrays.</p>
    754. 

  754. 

  755.             </div>
    756. 

  756.             
    757. 

  757.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">intersect</span></span> = (array) -&gt;
    758. 

  758.   rest = _.rest arguments
    759. 

  759.   _.select _.uniq(array), (item) -&gt;
    760. 

  760.     _.all rest, (other) -&gt;
    761. 

  761.       _.indexOf(other, item) &gt;= <span class="number">0</span></pre></div></div>
    762. 

  762.             
    763. 

  763.         </li>
    764. 

  764.         
    765. 

  765.         
    766. 

  766.         <li id="section-41">
    767. 

  767.             <div class="annotation">
    768. 

  768.               
    769. 

  769.               <div class="pilwrap ">
    770. 

  770.                 <a class="pilcrow" href="#section-41">&#182;</a>
    771. 

  771.               </div>
    772. 

  772.               <p>Zip together multiple lists into a single array -- elements that share
    773. 

  773. an index go together.</p>
    774. 

  774. 

  775.             </div>
    776. 

  776.             
    777. 

  777.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">zip</span></span> = -&gt;
    778. 

  778.   length =  _.max _.pluck arguments, <span class="string">'length'</span>
    779. 

  779.   results = <span class="keyword">new</span> Array length
    780. 

  780.   <span class="keyword">for</span> i <span class="keyword">in</span> [<span class="number">0.</span>..length]
    781. 

  781.     results[i] = _.pluck arguments, String i
    782. 

  782.   results</pre></div></div>
    783. 

  783.             
    784. 

  784.         </li>
    785. 

  785.         
    786. 

  786.         
    787. 

  787.         <li id="section-42">
    788. 

  788.             <div class="annotation">
    789. 

  789.               
    790. 

  790.               <div class="pilwrap ">
    791. 

  791.                 <a class="pilcrow" href="#section-42">&#182;</a>
    792. 

  792.               </div>
    793. 

  793.               <p>If the browser doesn&#39;t supply us with <strong>indexOf</strong> (I&#39;m looking at you, MSIE),
    794. 

  794. we need this function. Return the position of the first occurrence of an
    795. 

  795. item in an array, or -1 if the item is not included in the array.</p>
    796. 

  796. 

  797.             </div>
    798. 

  798.             
    799. 

  799.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">indexOf</span></span> = (array, item) -&gt;
    800. 

  800.   <span class="keyword">return</span> array.indexOf item <span class="keyword">if</span> nativeIndexOf <span class="keyword">and</span> array.indexOf <span class="keyword">is</span> nativeIndexOf
    801. 

  801.   i = <span class="number">0</span>; l = array.length
    802. 

  802.   <span class="keyword">while</span> l - i
    803. 

  803.     <span class="keyword">if</span> array[i] <span class="keyword">is</span> item <span class="keyword">then</span> <span class="keyword">return</span> i <span class="keyword">else</span> i++
    804. 

  804.   -<span class="number">1</span></pre></div></div>
    805. 

  805.             
    806. 

  806.         </li>
    807. 

  807.         
    808. 

  808.         
    809. 

  809.         <li id="section-43">
    810. 

  810.             <div class="annotation">
    811. 

  811.               
    812. 

  812.               <div class="pilwrap ">
    813. 

  813.                 <a class="pilcrow" href="#section-43">&#182;</a>
    814. 

  814.               </div>
    815. 

  815.               <p>Provide JavaScript 1.6&#39;s <strong>lastIndexOf</strong>, delegating to the native function,
    816. 

  816. if possible.</p>
    817. 

  817. 

  818.             </div>
    819. 

  819.             
    820. 

  820.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">lastIndexOf</span></span> = (array, item) -&gt;
    821. 

  821.   <span class="keyword">return</span> array.lastIndexOf(item) <span class="keyword">if</span> nativeLastIndexOf <span class="keyword">and</span> array.lastIndexOf <span class="keyword">is</span> nativeLastIndexOf
    822. 

  822.   i = array.length
    823. 

  823.   <span class="keyword">while</span> i
    824. 

  824.     <span class="keyword">if</span> array[i] <span class="keyword">is</span> item <span class="keyword">then</span> <span class="keyword">return</span> i <span class="keyword">else</span> i--
    825. 

  825.   -<span class="number">1</span></pre></div></div>
    826. 

  826.             
    827. 

  827.         </li>
    828. 

  828.         
    829. 

  829.         
    830. 

  830.         <li id="section-44">
    831. 

  831.             <div class="annotation">
    832. 

  832.               
    833. 

  833.               <div class="pilwrap ">
    834. 

  834.                 <a class="pilcrow" href="#section-44">&#182;</a>
    835. 

  835.               </div>
    836. 

  836.               <p>Generate an integer Array containing an arithmetic progression. A port of
    837. 

  837. <a href="http://docs.python.org/library/functions.html#range">the native Python <strong>range</strong> function</a>.</p>
    838. 

  838. 

  839.             </div>
    840. 

  840.             
    841. 

  841.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">range</span></span> = (start, stop, step) -&gt;
    842. 

  842.   a         = arguments
    843. 

  843.   solo      = a.length &lt;= <span class="number">1</span>
    844. 

  844.   i = start = <span class="keyword">if</span> solo <span class="keyword">then</span> <span class="number">0</span> <span class="keyword">else</span> a[<span class="number">0</span>]
    845. 

  845.   stop      = <span class="keyword">if</span> solo <span class="keyword">then</span> a[<span class="number">0</span>] <span class="keyword">else</span> a[<span class="number">1</span>]
    846. 

  846.   step      = a[<span class="number">2</span>] <span class="keyword">or</span> <span class="number">1</span>
    847. 

  847.   len       = Math.ceil((stop - start) / step)
    848. 

  848.   <span class="keyword">return</span> []   <span class="keyword">if</span> len &lt;= <span class="number">0</span>
    849. 

  849.   range     = <span class="keyword">new</span> Array len
    850. 

  850.   idx       = <span class="number">0</span>
    851. 

  851.   <span class="keyword">loop</span>
    852. 

  852.     <span class="keyword">return</span> range <span class="keyword">if</span> (<span class="keyword">if</span> step &gt; <span class="number">0</span> <span class="keyword">then</span> i - stop <span class="keyword">else</span> stop - i) &gt;= <span class="number">0</span>
    853. 

  853.     range[idx] = i
    854. 

  854.     idx++
    855. 

  855.     i+= step</pre></div></div>
    856. 

  856.             
    857. 

  857.         </li>
    858. 

  858.         
    859. 

  859.         
    860. 

  860.         <li id="section-45">
    861. 

  861.             <div class="annotation">
    862. 

  862.               
    863. 

  863.               <div class="pilwrap for-h2">
    864. 

  864.                 <a class="pilcrow" href="#section-45">&#182;</a>
    865. 

  865.               </div>
    866. 

  866.               <h2>Function Functions</h2>
    867. 

  867. 

  868.             </div>
    869. 

  869.             
    870. 

  870.         </li>
    871. 

  871.         
    872. 

  872.         
    873. 

  873.         <li id="section-46">
    874. 

  874.             <div class="annotation">
    875. 

  875.               
    876. 

  876.               <div class="pilwrap ">
    877. 

  877.                 <a class="pilcrow" href="#section-46">&#182;</a>
    878. 

  878.               </div>
    879. 

  879.               <p>Create a function bound to a given object (assigning <code>this</code>, and arguments,
    880. 

  880. optionally). Binding with arguments is also known as <strong>curry</strong>.</p>
    881. 

  881. 

  882.             </div>
    883. 

  883.             
    884. 

  884.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">bind</span></span> = (func, obj) -&gt;
    885. 

  885.   args = _.rest arguments, <span class="number">2</span>
    886. 

  886.   -&gt; func.apply obj <span class="keyword">or</span> root, args.concat arguments</pre></div></div>
    887. 

  887.             
    888. 

  888.         </li>
    889. 

  889.         
    890. 

  890.         
    891. 

  891.         <li id="section-47">
    892. 

  892.             <div class="annotation">
    893. 

  893.               
    894. 

  894.               <div class="pilwrap ">
    895. 

  895.                 <a class="pilcrow" href="#section-47">&#182;</a>
    896. 

  896.               </div>
    897. 

  897.               <p>Bind all of an object&#39;s methods to that object. Useful for ensuring that
    898. 

  898. all callbacks defined on an object belong to it.</p>
    899. 

  899. 

  900.             </div>
    901. 

  901.             
    902. 

  902.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">bindAll</span></span> = (obj) -&gt;
    903. 

  903.   funcs = <span class="keyword">if</span> arguments.length &gt; <span class="number">1</span> <span class="keyword">then</span> _.rest(arguments) <span class="keyword">else</span> _.functions(obj)
    904. 

  904.   _.each funcs, (f) -&gt; obj[f] = _.bind obj[f], obj
    905. 

  905.   obj</pre></div></div>
    906. 

  906.             
    907. 

  907.         </li>
    908. 

  908.         
    909. 

  909.         
    910. 

  910.         <li id="section-48">
    911. 

  911.             <div class="annotation">
    912. 

  912.               
    913. 

  913.               <div class="pilwrap ">
    914. 

  914.                 <a class="pilcrow" href="#section-48">&#182;</a>
    915. 

  915.               </div>
    916. 

  916.               <p>Delays a function for the given number of milliseconds, and then calls
    917. 

  917. it with the arguments supplied.</p>
    918. 

  918. 

  919.             </div>
    920. 

  920.             
    921. 

  921.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">delay</span></span> = (func, wait) -&gt;
    922. 

  922.   args = _.rest arguments, <span class="number">2</span>
    923. 

  923.   setTimeout((-&gt; func.apply(func, args)), wait)</pre></div></div>
    924. 

  924.             
    925. 

  925.         </li>
    926. 

  926.         
    927. 

  927.         
    928. 

  928.         <li id="section-49">
    929. 

  929.             <div class="annotation">
    930. 

  930.               
    931. 

  931.               <div class="pilwrap ">
    932. 

  932.                 <a class="pilcrow" href="#section-49">&#182;</a>
    933. 

  933.               </div>
    934. 

  934.               <p>Memoize an expensive function by storing its results.</p>
    935. 

  935. 

  936.             </div>
    937. 

  937.             
    938. 

  938.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">memoize</span></span> = (func, hasher) -&gt;
    939. 

  939.   memo = {}
    940. 

  940.   hasher <span class="keyword">or</span>= _.identity
    941. 

  941.   -&gt;
    942. 

  942.     key = hasher.apply <span class="keyword">this</span>, arguments
    943. 

  943.     <span class="keyword">return</span> memo[key] <span class="keyword">if</span> key <span class="keyword">of</span> memo
    944. 

  944.     memo[key] = func.apply <span class="keyword">this</span>, arguments</pre></div></div>
    945. 

  945.             
    946. 

  946.         </li>
    947. 

  947.         
    948. 

  948.         
    949. 

  949.         <li id="section-50">
    950. 

  950.             <div class="annotation">
    951. 

  951.               
    952. 

  952.               <div class="pilwrap ">
    953. 

  953.                 <a class="pilcrow" href="#section-50">&#182;</a>
    954. 

  954.               </div>
    955. 

  955.               <p>Defers a function, scheduling it to run after the current call stack has
    956. 

  956. cleared.</p>
    957. 

  957. 

  958.             </div>
    959. 

  959.             
    960. 

  960.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">defer</span></span> = (func) -&gt;
    961. 

  961.   _.delay.apply _, [func, <span class="number">1</span>].concat _.rest arguments</pre></div></div>
    962. 

  962.             
    963. 

  963.         </li>
    964. 

  964.         
    965. 

  965.         
    966. 

  966.         <li id="section-51">
    967. 

  967.             <div class="annotation">
    968. 

  968.               
    969. 

  969.               <div class="pilwrap ">
    970. 

  970.                 <a class="pilcrow" href="#section-51">&#182;</a>
    971. 

  971.               </div>
    972. 

  972.               <p>Returns the first function passed as an argument to the second,
    973. 

  973. allowing you to adjust arguments, run code before and after, and
    974. 

  974. conditionally execute the original function.</p>
    975. 

  975. 

  976.             </div>
    977. 

  977.             
    978. 

  978.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">wrap</span></span> = (func, wrapper) -&gt;
    979. 

  979.   -&gt; wrapper.apply wrapper, [func].concat arguments</pre></div></div>
    980. 

  980.             
    981. 

  981.         </li>
    982. 

  982.         
    983. 

  983.         
    984. 

  984.         <li id="section-52">
    985. 

  985.             <div class="annotation">
    986. 

  986.               
    987. 

  987.               <div class="pilwrap ">
    988. 

  988.                 <a class="pilcrow" href="#section-52">&#182;</a>
    989. 

  989.               </div>
    990. 

  990.               <p>Returns a function that is the composition of a list of functions, each
    991. 

  991. consuming the return value of the function that follows.</p>
    992. 

  992. 

  993.             </div>
    994. 

  994.             
    995. 

  995.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">compose</span></span> = -&gt;
    996. 

  996.   funcs = arguments
    997. 

  997.   -&gt;
    998. 

  998.     args = arguments
    999. 

  999.     <span class="keyword">for</span> i <span class="keyword">in</span> [funcs.length - <span class="number">1.</span><span class="number">.0</span>] <span class="keyword">by</span> -<span class="number">1</span>
    1000. 

  1000.       args = [funcs[i].apply(<span class="keyword">this</span>, args)]
    1001. 

  1001.     args[<span class="number">0</span>]</pre></div></div>
    1002. 

  1002.             
    1003. 

  1003.         </li>
    1004. 

  1004.         
    1005. 

  1005.         
    1006. 

  1006.         <li id="section-53">
    1007. 

  1007.             <div class="annotation">
    1008. 

  1008.               
    1009. 

  1009.               <div class="pilwrap for-h2">
    1010. 

  1010.                 <a class="pilcrow" href="#section-53">&#182;</a>
    1011. 

  1011.               </div>
    1012. 

  1012.               <h2>Object Functions</h2>
    1013. 

  1013. 

  1014.             </div>
    1015. 

  1015.             
    1016. 

  1016.         </li>
    1017. 

  1017.         
    1018. 

  1018.         
    1019. 

  1019.         <li id="section-54">
    1020. 

  1020.             <div class="annotation">
    1021. 

  1021.               
    1022. 

  1022.               <div class="pilwrap ">
    1023. 

  1023.                 <a class="pilcrow" href="#section-54">&#182;</a>
    1024. 

  1024.               </div>
    1025. 

  1025.               <p>Retrieve the names of an object&#39;s properties.</p>
    1026. 

  1026. 

  1027.             </div>
    1028. 

  1028.             
    1029. 

  1029.             <div class="content"><div class='highlight'><pre>_.keys = nativeKeys <span class="keyword">or</span> (obj) -&gt;
    1030. 

  1030.   <span class="keyword">return</span> _.range <span class="number">0</span>, obj.length <span class="keyword">if</span> _.isArray(obj)
    1031. 

  1031.   key <span class="keyword">for</span> key, val <span class="keyword">of</span> obj</pre></div></div>
    1032. 

  1032.             
    1033. 

  1033.         </li>
    1034. 

  1034.         
    1035. 

  1035.         
    1036. 

  1036.         <li id="section-55">
    1037. 

  1037.             <div class="annotation">
    1038. 

  1038.               
    1039. 

  1039.               <div class="pilwrap ">
    1040. 

  1040.                 <a class="pilcrow" href="#section-55">&#182;</a>
    1041. 

  1041.               </div>
    1042. 

  1042.               <p>Retrieve the values of an object&#39;s properties.</p>
    1043. 

  1043. 

  1044.             </div>
    1045. 

  1045.             
    1046. 

  1046.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">values</span></span> = (obj) -&gt;
    1047. 

  1047.   _.map obj, _.identity</pre></div></div>
    1048. 

  1048.             
    1049. 

  1049.         </li>
    1050. 

  1050.         
    1051. 

  1051.         
    1052. 

  1052.         <li id="section-56">
    1053. 

  1053.             <div class="annotation">
    1054. 

  1054.               
    1055. 

  1055.               <div class="pilwrap ">
    1056. 

  1056.                 <a class="pilcrow" href="#section-56">&#182;</a>
    1057. 

  1057.               </div>
    1058. 

  1058.               <p>Return a sorted list of the function names available in Underscore.</p>
    1059. 

  1059. 

  1060.             </div>
    1061. 

  1061.             
    1062. 

  1062.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">functions</span></span> = (obj) -&gt;
    1063. 

  1063.   _.filter(_.keys(obj), (key) -&gt; _.isFunction(obj[key])).sort()</pre></div></div>
    1064. 

  1064.             
    1065. 

  1065.         </li>
    1066. 

  1066.         
    1067. 

  1067.         
    1068. 

  1068.         <li id="section-57">
    1069. 

  1069.             <div class="annotation">
    1070. 

  1070.               
    1071. 

  1071.               <div class="pilwrap ">
    1072. 

  1072.                 <a class="pilcrow" href="#section-57">&#182;</a>
    1073. 

  1073.               </div>
    1074. 

  1074.               <p>Extend a given object with all of the properties in a source object.</p>
    1075. 

  1075. 

  1076.             </div>
    1077. 

  1077.             
    1078. 

  1078.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">extend</span></span> = (obj) -&gt;
    1079. 

  1079.   <span class="keyword">for</span> source <span class="keyword">in</span> _.rest(arguments)
    1080. 

  1080.     obj[key] = val <span class="keyword">for</span> key, val <span class="keyword">of</span> source
    1081. 

  1081.   obj</pre></div></div>
    1082. 

  1082.             
    1083. 

  1083.         </li>
    1084. 

  1084.         
    1085. 

  1085.         
    1086. 

  1086.         <li id="section-58">
    1087. 

  1087.             <div class="annotation">
    1088. 

  1088.               
    1089. 

  1089.               <div class="pilwrap ">
    1090. 

  1090.                 <a class="pilcrow" href="#section-58">&#182;</a>
    1091. 

  1091.               </div>
    1092. 

  1092.               <p>Create a (shallow-cloned) duplicate of an object.</p>
    1093. 

  1093. 

  1094.             </div>
    1095. 

  1095.             
    1096. 

  1096.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">clone</span></span> = (obj) -&gt;
    1097. 

  1097.   <span class="keyword">return</span> obj.slice <span class="number">0</span> <span class="keyword">if</span> _.isArray obj
    1098. 

  1098.   _.extend {}, obj</pre></div></div>
    1099. 

  1099.             
    1100. 

  1100.         </li>
    1101. 

  1101.         
    1102. 

  1102.         
    1103. 

  1103.         <li id="section-59">
    1104. 

  1104.             <div class="annotation">
    1105. 

  1105.               
    1106. 

  1106.               <div class="pilwrap ">
    1107. 

  1107.                 <a class="pilcrow" href="#section-59">&#182;</a>
    1108. 

  1108.               </div>
    1109. 

  1109.               <p>Invokes interceptor with the obj, and then returns obj.
    1110. 

  1110. The primary purpose of this method is to &quot;tap into&quot; a method chain, in order to perform operations on intermediate results within the chain.</p>
    1111. 

  1111. 

  1112.             </div>
    1113. 

  1113.             
    1114. 

  1114.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">tap</span></span> = (obj, interceptor) -&gt;
    1115. 

  1115.   interceptor obj
    1116. 

  1116.   obj</pre></div></div>
    1117. 

  1117.             
    1118. 

  1118.         </li>
    1119. 

  1119.         
    1120. 

  1120.         
    1121. 

  1121.         <li id="section-60">
    1122. 

  1122.             <div class="annotation">
    1123. 

  1123.               
    1124. 

  1124.               <div class="pilwrap ">
    1125. 

  1125.                 <a class="pilcrow" href="#section-60">&#182;</a>
    1126. 

  1126.               </div>
    1127. 

  1127.               <p>Perform a deep comparison to check if two objects are equal.</p>
    1128. 

  1128. 

  1129.             </div>
    1130. 

  1130.             
    1131. 

  1131.             <div class="content"><div class='highlight'><pre>_.<span class="function"><span class="title">isEqual</span></span> = (a, b) -&gt;</pre></div></div>
    1132. 

  1132.             
    1133. 

  1133.         </li>
    1134. 

  1134.         
    1135. 

  1135.         
    1136. 

  1136.         <li id="section-61">
    1137. 

  1137.             <div class="annotation">
    1138. 

  1138.               
    1139. 

  1139.               <div class="pilwrap ">
    1140. 

  1140.                 <a class="pilcrow" href="#section-61">&#182;</a>
    1141. 

  1141.               </div>
    1142. 

  1142.               <p>Check object identity.</p>
    1143. 

  1143. 

  1144.             </div>
    1145. 

  1145.             
    1146. 

  1146.             <div class="content"><div class='highlight'><pre>  <span class="keyword">return</span> <span class="literal">true</span> <span class="keyword">if</span> a <span class="keyword">is</span> b</pre></div></div>
    1147. 

  1147.             
    1148. 

  1148.         </li>
    1149. 

  1149.         
    1150. 

  1150.         
    1151. 

  1151.         <li id="section-62">
    1152. 

  1152.             <div class="annotation">
    1153. 

  1153.               
    1154. 

  1154.               <div class="pilwrap ">
    1155. 

  1155.                 <a class="pilcrow" href="#section-62">&#182;</a>
    1156. 

  1156.               </div>
    1157. 

  1157.               <p>Different types?</p>
    1158. 

  1158. 

  1159.             </div>
    1160. 

  1160.             
    1161. 

  1161.             <div class="content"><div class='highlight'><pre>  atype = <span class="keyword">typeof</span>(a); btype = <span class="keyword">typeof</span>(b)
    1162. 

  1162.   <span class="keyword">return</span> <span class="literal">false</span> <span class="keyword">if</span> atype <span class="keyword">isnt</span> btype</pre></div></div>
    1163. 

  1163.             
    1164. 

  1164.         </li>
    1165. 

  1165.         
    1166. 

  1166.         
    1167. 

  1167.         <li id="section-63">
    1168. 

  1168.             <div class="annotation">
    1169. 

  1169.               
    1170. 

  1170.               <div class="pilwrap ">
    1171. 

  1171.                 <a class="pilcrow" href="#section-63">&#182;</a>
    1172. 

  1172.               </div>
    1173. 

  1173.               <p>Basic equality test (watch out for coercions).</p>
    1174. 

  1174. 

  1175.             </div>
    1176. 

  1176.             
    1177. 

  1177.             <div class="content"><div class='highlight'><pre>  <span class="keyword">return</span> <span class="literal">true</span> <span class="keyword">if</span> `<span class="javascript">a == b</span>`</pre></div></div>
    1178. 

  1178.             
    1179. 

  1179.         </li>
    1180. 

  1180.         
    1181. 

  1181.         
    1182. 

  1182.         <li id="section-64">
    1183. 

  1183.             <div class="annotation">
    1184. 

  1184.               
    1185. 

  1185.               <div class="pilwrap ">
    1186. 

  1186.                 <a class="pilcrow" href="#section-64">&#182;</a>
    1187. 

  1187.               </div>
    1188. 

  1188.               <p>One is falsy and the other truthy.</p>…
    1189.