/node_modules/underscore/index.html
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- <body>
- <div id="sidebar" class="interface">
- <a class="toc_title" href="#">
- Underscore.js <span class="version">(1.4.0)</span>
- </a>
- <a class="toc_title" href="#">
- Introduction
- </a>
- <a class="toc_title" href="#collections">
- Collections
- </a>
- <ul class="toc_section">
- <li>- <a href="#each">each</a></li>
- <li>- <a href="#map">map</a></li>
- <li>- <a href="#reduce">reduce</a></li>
- <li>- <a href="#reduceRight">reduceRight</a></li>
- <li>- <a href="#find">find</a></li>
- <li>- <a href="#filter">filter</a></li>
- <li>- <a href="#where">where</a></li>
- <li>- <a href="#reject">reject</a></li>
- <li>- <a href="#all">all</a></li>
- <li>- <a href="#any">any</a></li>
- <li>- <a href="#contains">contains</a></li>
- <li>- <a href="#invoke">invoke</a></li>
- <li>- <a href="#pluck">pluck</a></li>
- <li>- <a href="#max">max</a></li>
- <li>- <a href="#min">min</a></li>
- <li>- <a href="#sortBy">sortBy</a></li>
- <li>- <a href="#groupBy">groupBy</a></li>
- <li>- <a href="#countBy">countBy</a></li>
- <li>- <a href="#shuffle">shuffle</a></li>
- <li>- <a href="#toArray">toArray</a></li>
- <li>- <a href="#size">size</a></li>
- </ul>
- <a class="toc_title" href="#arrays">
- Arrays
- </a>
- <ul class="toc_section">
- <li>- <a href="#first">first</a></li>
- <li>- <a href="#initial">initial</a></li>
- <li>- <a href="#last">last</a></li>
- <li>- <a href="#rest">rest</a></li>
- <li>- <a href="#compact">compact</a></li>
- <li>- <a href="#flatten">flatten</a></li>
- <li>- <a href="#without">without</a></li>
- <li>- <a href="#union">union</a></li>
- <li>- <a href="#intersection">intersection</a></li>
- <li>- <a href="#difference">difference</a></li>
- <li>- <a href="#uniq">uniq</a></li>
- <li>- <a href="#zip">zip</a></li>
- <li>- <a href="#object">object</a></li>
- <li>- <a href="#indexOf">indexOf</a></li>
- <li>- <a href="#lastIndexOf">lastIndexOf</a></li>
- <li>- <a href="#sortedIndex">sortedIndex</a></li>
- <li>- <a href="#range">range</a></li>
- </ul>
- <a class="toc_title" href="#functions">
- Functions
- </a>
- <ul class="toc_section">
- <li>- <a href="#bind">bind</a></li>
- <li>- <a href="#bindAll">bindAll</a></li>
- <li>- <a href="#memoize">memoize</a></li>
- <li>- <a href="#delay">delay</a></li>
- <li>- <a href="#defer">defer</a></li>
- <li>- <a href="#throttle">throttle</a></li>
- <li>- <a href="#debounce">debounce</a></li>
- <li>- <a href="#once">once</a></li>
- <li>- <a href="#after">after</a></li>
- <li>- <a href="#wrap">wrap</a></li>
- <li>- <a href="#compose">compose</a></li>
- </ul>
- <a class="toc_title" href="#objects">
- Objects
- </a>
- <ul class="toc_section">
- <li>- <a href="#keys">keys</a></li>
- <li>- <a href="#values">values</a></li>
- <li>- <a href="#pairs">pairs</a></li>
- <li>- <a href="#invert">invert</a></li>
- <li>- <a href="#object-functions">functions</a></li>
- <li>- <a href="#extend">extend</a></li>
- <li>- <a href="#pick">pick</a></li>
- <li>- <a href="#omit">omit</a></li>
- <li>- <a href="#defaults">defaults</a></li>
- <li>- <a href="#clone">clone</a></li>
- <li>- <a href="#tap">tap</a></li>
- <li>- <a href="#has">has</a></li>
- <li>- <a href="#isEqual">isEqual</a></li>
- <li>- <a href="#isEmpty">isEmpty</a></li>
- <li>- <a href="#isElement">isElement</a></li>
- <li>- <a href="#isArray">isArray</a></li>
- <li>- <a href="#isObject">isObject</a></li>
- <li>- <a href="#isArguments">isArguments</a></li>
- <li>- <a href="#isFunction">isFunction</a></li>
- <li>- <a href="#isString">isString</a></li>
- <li>- <a href="#isNumber">isNumber</a></li>
- <li>- <a href="#isFinite">isFinite</a></li>
- <li>- <a href="#isBoolean">isBoolean</a></li>
- <li>- <a href="#isDate">isDate</a></li>
- <li>- <a href="#isRegExp">isRegExp</a></li>
- <li>- <a href="#isNaN">isNaN</a></li>
- <li>- <a href="#isNull">isNull</a></li>
- <li>- <a href="#isUndefined">isUndefined</a></li>
- </ul>
- <a class="toc_title" href="#utility">
- Utility
- </a>
- <ul class="toc_section">
- <li>- <a href="#noConflict">noConflict</a></li>
- <li>- <a href="#identity">identity</a></li>
- <li>- <a href="#times">times</a></li>
- <li>- <a href="#random">random</a></li>
- <li>- <a href="#mixin">mixin</a></li>
- <li>- <a href="#uniqueId">uniqueId</a></li>
- <li>- <a href="#escape">escape</a></li>
- <li>- <a href="#result">result</a></li>
- <li>- <a href="#template">template</a></li>
- </ul>
- <a class="toc_title" href="#chaining">
- Chaining
- </a>
- <ul class="toc_section">
- <li>- <a href="#chain">chain</a></li>
- <li>- <a href="#value">value</a></li>
- </ul>
- <a class="toc_title" href="#links">
- Links
- </a>
- <a class="toc_title" href="#changelog">
- Change Log
- </a>
- </div>
- <div class="container">
- <p id="introduction">
- <img id="logo" src="docs/images/underscore.png" alt="Underscore.js" />
- </p>
- <p>
- <a href="http://github.com/documentcloud/underscore/">Underscore</a> is a
- utility-belt library for JavaScript that provides a lot of the
- functional programming support that you would expect in
- <a href="http://prototypejs.org/api">Prototype.js</a>
- (or <a href="http://www.ruby-doc.org/core/classes/Enumerable.html">Ruby</a>),
- but without extending any of the built-in JavaScript objects. It's the
- tie to go along with <a href="http://docs.jquery.com">jQuery</a>'s tux,
- and <a href="http://backbonejs.org">Backbone.js</a>'s suspenders.
- </p>
- <p>
- Underscore provides 80-odd functions that support both the usual
- functional suspects: <b>map</b>, <b>select</b>, <b>invoke</b> —
- as well as more specialized helpers: function binding, javascript
- templating, deep equality testing, and so on. It delegates to built-in
- functions, if present, so modern browsers will use the
- native implementations of <b>forEach</b>, <b>map</b>, <b>reduce</b>,
- <b>filter</b>, <b>every</b>, <b>some</b> and <b>indexOf</b>.
- </p>
- <p>
- A complete <a href="test/">Test & Benchmark Suite</a>
- is included for your perusal.
- </p>
- <p>
- You may also read through the <a href="docs/underscore.html">annotated source code</a>.
- </p>
- <p>
- The project is
- <a href="http://github.com/documentcloud/underscore/">hosted on GitHub</a>.
- You can report bugs and discuss features on the
- <a href="http://github.com/documentcloud/underscore/issues">issues page</a>,
- on Freenode in the <tt>#documentcloud</tt> channel,
- or send tweets to <a href="http://twitter.com/documentcloud">@documentcloud</a>.
- </p>
- <p>
- <i>Underscore is an open-source component of <a href="http://documentcloud.org/">DocumentCloud</a>.</i>
- </p>
- <h2>Downloads <i style="padding-left: 12px; font-size:12px;">(Right-click, and use "Save As")</i></h2>
- <table>
- <tr>
- <td><a href="underscore.js">Development Version (1.4.0)</a></td>
- <td><i>40kb, Uncompressed with Plentiful Comments</i></td>
- </tr>
- <tr>
- <td><a href="underscore-min.js">Production Version (1.4.0)</a></td>
- <td><i>4kb, Minified and Gzipped</i></td>
- </tr>
- <tr>
- <td colspan="2"><div class="rule"></div></td>
- </tr>
- <tr>
- <td><a href="https://raw.github.com/documentcloud/underscore/master/underscore.js">Edge Version</a></td>
- <td><i>Unreleased, current <tt>master</tt>, use at your own risk</i></td>
- </tr>
- </table>
- <div id="documentation">
- <h2 id="collections">Collection Functions (Arrays or Objects)</h2>
- <p id="each">
- <b class="header">each</b><code>_.each(list, iterator, [context])</code>
- <span class="alias">Alias: <b>forEach</b></span>
- <br />
- Iterates over a <b>list</b> of elements, yielding each in turn to an <b>iterator</b>
- function. The <b>iterator</b> is bound to the <b>context</b> object, if one is
- passed. Each invocation of <b>iterator</b> is called with three arguments:
- <tt>(element, index, list)</tt>. If <b>list</b> is a JavaScript object, <b>iterator</b>'s
- arguments will be <tt>(value, key, list)</tt>. Delegates to the native
- <b>forEach</b> function if it exists.
- </p>
- <pre>
- _.each([1, 2, 3], function(num){ alert(num); });
- => alerts each number in turn...
- _.each({one : 1, two : 2, three : 3}, function(num, key){ alert(num); });
- => alerts each number in turn...</pre>
- <p id="map">
- <b class="header">map</b><code>_.map(list, iterator, [context])</code>
- <span class="alias">Alias: <b>collect</b></span>
- <br />
- Produces a new array of values by mapping each value in <b>list</b>
- through a transformation function (<b>iterator</b>). If the native <b>map</b> method
- exists, it will be used instead. If <b>list</b> is a JavaScript object,
- <b>iterator</b>'s arguments will be <tt>(value, key, list)</tt>.
- </p>
- <pre>
- _.map([1, 2, 3], function(num){ return num * 3; });
- => [3, 6, 9]
- _.map({one : 1, two : 2, three : 3}, function(num, key){ return num * 3; });
- => [3, 6, 9]</pre>
- <p id="reduce">
- <b class="header">reduce</b><code>_.reduce(list, iterator, memo, [context])</code>
- <span class="alias">Aliases: <b>inject, foldl</b></span>
- <br />
- Also known as <b>inject</b> and <b>foldl</b>, <b>reduce</b> boils down a
- <b>list</b> of values into a single value. <b>Memo</b> is the initial state
- of the reduction, and each successive step of it should be returned by
- <b>iterator</b>. The iterator is passed four arguments: the <tt>memo</tt>,
- then the <tt>value</tt> and <tt>index</tt> (or key) of the iteration,
- and finally a reference to the entire <tt>list</tt>.
- </p>
- <pre>
- var sum = _.reduce([1, 2, 3], function(memo, num){ return memo + num; }, 0);
- => 6
- </pre>
- <p id="reduceRight">
- <b class="header">reduceRight</b><code>_.reduceRight(list, iterator, memo, [context])</code>
- <span class="alias">Alias: <b>foldr</b></span>
- <br />
- The right-associative version of <b>reduce</b>. Delegates to the
- JavaScript 1.8 version of <b>reduceRight</b>, if it exists. <b>Foldr</b>
- is not as useful in JavaScript as it would be in a language with lazy
- evaluation.
- </p>
- <pre>
- var list = [[0, 1], [2, 3], [4, 5]];
- var flat = _.reduceRight(list, function(a, b) { return a.concat(b); }, []);
- => [4, 5, 2, 3, 0, 1]
- </pre>
- <p id="find">
- <b class="header">find</b><code>_.find(list, iterator, [context])</code>
- <span class="alias">Alias: <b>detect</b></span>
- <br />
- Looks through each value in the <b>list</b>, returning the first one that
- passes a truth test (<b>iterator</b>). The function returns as
- soon as it finds an acceptable element, and doesn't traverse the
- entire list.
- </p>
- <pre>
- var even = _.find([1, 2, 3, 4, 5, 6], function(num){ return num % 2 == 0; });
- => 2
- </pre>
- <p id="filter">
- <b class="header">filter</b><code>_.filter(list, iterator, [context])</code>
- <span class="alias">Alias: <b>select</b></span>
- <br />
- Looks through each value in the <b>list</b>, returning an array of all
- the values that pass a truth test (<b>iterator</b>). Delegates to the
- native <b>filter</b> method, if it exists.
- </p>
- <pre>
- var evens = _.filter([1, 2, 3, 4, 5, 6], function(num){ return num % 2 == 0; });
- => [2, 4, 6]
- </pre>
- <p id="where">
- <b class="header">where</b><code>_.where(list, properties)</code>
- <br />
- Looks through each value in the <b>list</b>, returning an array of all
- the values that contain all of the key-value pairs listed in <b>properties</b>.
- </p>
- <pre>
- _.where(listOfPlays, {author: "Shakespeare", year: 1611});
- => [{title: "Cymbeline", author: "Shakespeare", year: 1611},
- {title: "The Tempest", author: "Shakespeare", year: 1611}]
- </pre>
- <p id="reject">
- <b class="header">reject</b><code>_.reject(list, iterator, [context])</code>
- <br />
- Returns the values in <b>list</b> without the elements that the truth
- test (<b>iterator</b>) passes. The opposite of <b>filter</b>.
- </p>
- <pre>
- var odds = _.reject([1, 2, 3, 4, 5, 6], function(num){ return num % 2 == 0; });
- => [1, 3, 5]
- </pre>
- <p id="all">
- <b class="header">all</b><code>_.all(list, iterator, [context])</code>
- <span class="alias">Alias: <b>every</b></span>
- <br />
- Returns <i>true</i> if all of the values in the <b>list</b> pass the <b>iterator</b>
- truth test. Delegates to the native method <b>every</b>, if present.
- </p>
- <pre>
- _.all([true, 1, null, 'yes'], _.identity);
- => false
- </pre>
- <p id="any">
- <b class="header">any</b><code>_.any(list, [iterator], [context])</code>
- <span class="alias">Alias: <b>some</b></span>
- <br />
- Returns <i>true</i> if any of the values in the <b>list</b> pass the
- <b>iterator</b> truth test. Short-circuits and stops traversing the list
- if a true element is found. Delegates to the native method <b>some</b>,
- if present.
- </p>
- <pre>
- _.any([null, 0, 'yes', false]);
- => true
- </pre>
- <p id="contains">
- <b class="header">contains</b><code>_.contains(list, value)</code>
- <span class="alias">Alias: <b>include</b></span>
- <br />
- Returns <i>true</i> if the <b>value</b> is present in the <b>list</b>.
- Uses <b>indexOf</b> internally, if <b>list</b> is an Array.
- </p>
- <pre>
- _.contains([1, 2, 3], 3);
- => true
- </pre>
- <p id="invoke">
- <b class="header">invoke</b><code>_.invoke(list, methodName, [*arguments])</code>
- <br />
- Calls the method named by <b>methodName</b> on each value in the <b>list</b>.
- Any extra arguments passed to <b>invoke</b> will be forwarded on to the
- method invocation.
- </p>
- <pre>
- _.invoke([[5, 1, 7], [3, 2, 1]], 'sort');
- => [[1, 5, 7], [1, 2, 3]]
- </pre>
- <p id="pluck">
- <b class="header">pluck</b><code>_.pluck(list, propertyName)</code>
- <br />
- A convenient version of what is perhaps the most common use-case for
- <b>map</b>: extracting a list of property values.
- </p>
- <pre>
- var stooges = [{name : 'moe', age : 40}, {name : 'larry', age : 50}, {name : 'curly', age : 60}];
- _.pluck(stooges, 'name');
- => ["moe", "larry", "curly"]
- </pre>
- <p id="max">
- <b class="header">max</b><code>_.max(list, [iterator], [context])</code>
- <br />
- Returns the maximum value in <b>list</b>. If <b>iterator</b> is passed,
- it will be used on each value to generate the criterion by which the
- value is ranked.
- </p>
- <pre>
- var stooges = [{name : 'moe', age : 40}, {name : 'larry', age : 50}, {name : 'curly', age : 60}];
- _.max(stooges, function(stooge){ return stooge.age; });
- => {name : 'curly', age : 60};
- </pre>
- <p id="min">
- <b class="header">min</b><code>_.min(list, [iterator], [context])</code>
- <br />
- Returns the minimum value in <b>list</b>. If <b>iterator</b> is passed,
- it will be used on each value to generate the criterion by which the
- value is ranked.
- </p>
- <pre>
- var numbers = [10, 5, 100, 2, 1000];
- _.min(numbers);
- => 2
- </pre>
- <p id="sortBy">
- <b class="header">sortBy</b><code>_.sortBy(list, iterator, [context])</code>
- <br />
- Returns a sorted copy of <b>list</b>, ranked in ascending order by the
- results of running each value through <b>iterator</b>. Iterator may
- also be the string name of the property to sort by (eg. <tt>length</tt>).
- </p>
- <pre>
- _.sortBy([1, 2, 3, 4, 5, 6], function(num){ return Math.sin(num); });
- => [5, 4, 6, 3, 1, 2]
- </pre>
- <p id="groupBy">
- <b class="header">groupBy</b><code>_.groupBy(list, iterator)</code>
- <br />
- Splits a collection into sets, grouped by the result of running each
- value through <b>iterator</b>. If <b>iterator</b> is a string instead of
- a function, groups by the property named by <b>iterator</b> on each of
- the values.
- </p>
- <pre>
- _.groupBy([1.3, 2.1, 2.4], function(num){ return Math.floor(num); });
- => {1: [1.3], 2: [2.1, 2.4]}
- _.groupBy(['one', 'two', 'three'], 'length');
- => {3: ["one", "two"], 5: ["three"]}
- </pre>
- <p id="countBy">
- <b class="header">countBy</b><code>_.countBy(list, iterator)</code>
- <br />
- Sorts a list into groups and returns a count for the number of objects
- in each group.
- Similar to <tt>groupBy</tt>, but instead of returning a list of values,
- returns a count for the number of values in that group.
- </p>
- <pre>
- _.countBy([1, 2, 3, 4, 5], function(num) {
- return num % 2 == 0 ? 'even' : 'odd';
- });
- => {odd: 3, even: 2}
- </pre>
- <p id="shuffle">
- <b class="header">shuffle</b><code>_.shuffle(list)</code>
- <br />
- Returns a shuffled copy of the <b>list</b>, using a version of the
- <a href="http://en.wikipedia.org/wiki/Fisher%E2%80%93Yates_shuffle">Fisher-Yates shuffle</a>.
- </p>
- <pre>
- _.shuffle([1, 2, 3, 4, 5, 6]);
- => [4, 1, 6, 3, 5, 2]
- </pre>
- <p id="toArray">
- <b class="header">toArray</b><code>_.toArray(list)</code>
- <br />
- Converts the <b>list</b> (anything that can be iterated over), into a
- real Array. Useful for transmuting the <b>arguments</b> object.
- </p>
- <pre>
- (function(){ return _.toArray(arguments).slice(1); })(1, 2, 3, 4);
- => [2, 3, 4]
- </pre>
- <p id="size">
- <b class="header">size</b><code>_.size(list)</code>
- <br />
- Return the number of values in the <b>list</b>.
- </p>
- <pre>
- _.size({one : 1, two : 2, three : 3});
- => 3
- </pre>
- <h2 id="arrays">Array Functions</h2>
- <p>
- <i>
- Note: All array functions will also work on the <b>arguments</b> object.
- However, Underscore functions are not designed to work on "sparse" arrays.
- </i>
- </p>
- <p id="first">
- <b class="header">first</b><code>_.first(array, [n])</code>
- <span class="alias">Alias: <b>head</b>, <b>take</b></span>
- <br />
- Returns the first element of an <b>array</b>. Passing <b>n</b> will
- return the first <b>n</b> elements of the array.
- </p>
- <pre>
- _.first([5, 4, 3, 2, 1]);
- => 5
- </pre>
- <p id="initial">
- <b class="header">initial</b><code>_.initial(array, [n])</code>
- <br />
- Returns everything but the last entry of the array. Especially useful on
- the arguments object. Pass <b>n</b> to exclude the last <b>n</b> elements
- from the result.
- </p>
- <pre>
- _.initial([5, 4, 3, 2, 1]);
- => [5, 4, 3, 2]
- </pre>
- <p id="last">
- <b class="header">last</b><code>_.last(array, [n])</code>
- <br />
- Returns the last element of an <b>array</b>. Passing <b>n</b> will return
- the last <b>n</b> elements of the array.
- </p>
- <pre>
- _.last([5, 4, 3, 2, 1]);
- => 1
- </pre>
- <p id="rest">
- <b class="header">rest</b><code>_.rest(array, [index])</code>
- <span class="alias">Alias: <b>tail, drop</b></span>
- <br />
- Returns the <b>rest</b> of the elements in an array. Pass an <b>index</b>
- to return the values of the array from that index onward.
- </p>
- <pre>
- _.rest([5, 4, 3, 2, 1]);
- => [4, 3, 2, 1]
- </pre>
- <p id="compact">
- <b class="header">compact</b><code>_.compact(array)</code>
- <br />
- Returns a copy of the <b>array</b> with all falsy values removed.
- In JavaScript, <i>false</i>, <i>null</i>, <i>0</i>, <i>""</i>,
- <i>undefined</i> and <i>NaN</i> are all falsy.
- </p>
- <pre>
- _.compact([0, 1, false, 2, '', 3]);
- => [1, 2, 3]
- </pre>
- <p id="flatten">
- <b class="header">flatten</b><code>_.flatten(array, [shallow])</code>
- <br />
- Flattens a nested <b>array</b> (the nesting can be to any depth). If you
- pass <b>shallow</b>, the array will only be flattened a single level.
- </p>
- <pre>
- _.flatten([1, [2], [3, [[4]]]]);
- => [1, 2, 3, 4];
- _.flatten([1, [2], [3, [[4]]]], true);
- => [1, 2, 3, [[4]]];
- </pre>
- <p id="without">
- <b class="header">without</b><code>_.without(array, [*values])</code>
- <br />
- Returns a copy of the <b>array</b> with all instances of the <b>values</b>
- removed.
- </p>
- <pre>
- _.without([1, 2, 1, 0, 3, 1, 4], 0, 1);
- => [2, 3, 4]
- </pre>
- <p id="union">
- <b class="header">union</b><code>_.union(*arrays)</code>
- <br />
- Computes the union of the passed-in <b>arrays</b>: the list of unique items,
- in order, that are present in one or more of the <b>arrays</b>.
- </p>
- <pre>
- _.union([1, 2, 3], [101, 2, 1, 10], [2, 1]);
- => [1, 2, 3, 101, 10]
- </pre>
- <p id="intersection">
- <b class="header">intersection</b><code>_.intersection(*arrays)</code>
- <br />
- Computes the list of values that are the intersection of all the <b>arrays</b>.
- Each value in the result is present in each of the <b>arrays</b>.
- </p>
- <pre>
- _.intersection([1, 2, 3], [101, 2, 1, 10], [2, 1]);
- => [1, 2]
- </pre>
- <p id="difference">
- <b class="header">difference</b><code>_.difference(array, *others)</code>
- <br />
- Similar to <b>without</b>, but returns the values from <b>array</b> that
- are not present in the <b>other</b> arrays.
- </p>
- <pre>
- _.difference([1, 2, 3, 4, 5], [5, 2, 10]);
- => [1, 3, 4]
- </pre>
- <p id="uniq">
- <b class="header">uniq</b><code>_.uniq(array, [isSorted], [iterator])</code>
- <span class="alias">Alias: <b>unique</b></span>
- <br />
- Produces a duplicate-free version of the <b>array</b>, using <i>===</i> to test
- object equality. If you know in advance that the <b>array</b> is sorted,
- passing <i>true</i> for <b>isSorted</b> will run a much faster algorithm.
- If you want to compute unique items based on a transformation, pass an
- <b>iterator</b> function.
- </p>
- <pre>
- _.uniq([1, 2, 1, 3, 1, 4]);
- => [1, 2, 3, 4]
- </pre>
- <p id="zip">
- <b class="header">zip</b><code>_.zip(*arrays)</code>
- <br />
- Merges together the values of each of the <b>arrays</b> with the
- values at the corresponding position. Useful when you have separate
- data sources that are coordinated through matching array indexes.
- If you're working with a matrix of nested arrays, <b>zip.apply</b>
- can transpose the matrix in a similar fashion.
- </p>
- <pre>
- _.zip(['moe', 'larry', 'curly'], [30, 40, 50], [true, false, false]);
- => [["moe", 30, true], ["larry", 40, false], ["curly", 50, false]]
- </pre>
- <p id="object">
- <b class="header">object</b><code>_.object(list, [values])</code>
- <br />
- Converts arrays into objects. Pass either a single list of
- <tt>[key, value]</tt> pairs, or a list of keys, and a list of values.
- </p>
- <pre>
- _.object(['moe', 'larry', 'curly'], [30, 40, 50]);
- => {moe: 30, larry: 40, curly: 50}
- _.object([['moe', 30], ['larry', 40], ['curly', 50]]);
- => {moe: 30, larry: 40, curly: 50}
- </pre>
- <p id="indexOf">
- <b class="header">indexOf</b><code>_.indexOf(array, value, [isSorted])</code>
- <br />
- Returns the index at which <b>value</b> can be found in the <b>array</b>,
- or <i>-1</i> if value is not present in the <b>array</b>. Uses the native
- <b>indexOf</b> function unless it's missing. If you're working with a
- large array, and you know that the array is already sorted, pass <tt>true</tt>
- for <b>isSorted</b> to use a faster binary search ... or, pass a number as
- the third argument in order to look for the first matching value in the
- array after the given index.
- </p>
- <pre>
- _.indexOf([1, 2, 3], 2);
- => 1
- </pre>
- <p id="lastIndexOf">
- <b class="header">lastIndexOf</b><code>_.lastIndexOf(array, value, [fromIndex])</code>
- <br />
- Returns the index of the last occurrence of <b>value</b> in the <b>array</b>,
- or <i>-1</i> if value is not present. Uses the native <b>lastIndexOf</b>
- function if possible. Pass <b>fromIndex</b> to start your search at a
- given index.
- </p>
- <pre>
- _.lastIndexOf([1, 2, 3, 1, 2, 3], 2);
- => 4
- </pre>
- <p id="sortedIndex">
- <b class="header">sortedIndex</b><code>_.sortedIndex(list, value, [iterator])</code>
- <br />
- Uses a binary search to determine the index at which the <b>value</b>
- <i>should</i> be inserted into the <b>list</b> in order to maintain the <b>list</b>'s
- sorted order. If an <b>iterator</b> is passed, it will be used to compute
- the sort ranking of each value, including the <b>value</b> you pass.
- </p>
- <pre>
- _.sortedIndex([10, 20, 30, 40, 50], 35);
- => 3
- </pre>
- <p id="range">
- <b class="header">range</b><code>_.range([start], stop, [step])</code>
- <br />
- A function to create flexibly-numbered lists of integers, handy for
- <tt>each</tt> and <tt>map</tt> loops. <b>start</b>, if omitted, defaults
- to <i>0</i>; <b>step</b> defaults to <i>1</i>. Returns a list of integers
- from <b>start</b> to <b>stop</b>, incremented (or decremented) by <b>step</b>,
- exclusive.
- </p>
- <pre>
- _.range(10);
- => [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
- _.range(1, 11);
- => [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
- _.range(0, 30, 5);
- => [0, 5, 10, 15, 20, 25]
- _.range(0, -10, -1);
- => [0, -1, -2, -3, -4, -5, -6, -7, -8, -9]
- _.range(0);
- => []
- </pre>
- <h2 id="functions">Function (uh, ahem) Functions</h2>
- <p id="bind">
- <b class="header">bind</b><code>_.bind(function, object, [*arguments])</code>
- <br />
- Bind a <b>function</b> to an <b>object</b>, meaning that whenever
- the function is called, the value of <i>this</i> will be the <b>object</b>.
- Optionally, bind <b>arguments</b> to the <b>function</b> to pre-fill them,
- also known as <b>partial application</b>.
- </p>
- <pre>
- var func = function(greeting){ return greeting + ': ' + this.name };
- func = _.bind(func, {name : 'moe'}, 'hi');
- func();
- => 'hi: moe'
- </pre>
- <p id="bindAll">
- <b class="header">bindAll</b><code>_.bindAll(object, [*methodNames])</code>
- <br />
- Binds a number of methods on the <b>object</b>, specified by
- <b>methodNames</b>, to be run in the context of that object whenever they
- are invoked. Very handy for binding functions that are going to be used
- as event handlers, which would otherwise be invoked with a fairly useless
- <i>this</i>. If no <b>methodNames</b> are provided, all of the object's
- function properties will be bound to it.
- </p>
- <pre>
- var buttonView = {
- label : 'underscore',
- onClick : function(){ alert('clicked: ' + this.label); },
- onHover : function(){ console.log('hovering: ' + this.label); }
- };
- _.bindAll(buttonView);
- jQuery('#underscore_button').bind('click', buttonView.onClick);
- => When the button is clicked, this.label will have the correct value...
- </pre>
- <p id="memoize">
- <b class="header">memoize</b><code>_.memoize(function, [hashFunction])</code>
- <br />
- Memoizes a given <b>function</b> by caching the computed result. Useful
- for speeding up slow-running computations. If passed an optional
- <b>hashFunction</b>, it will be used to compute the hash key for storing
- the result, based on the arguments to the original function. The default
- <b>hashFunction</b> just uses the first argument to the memoized function
- as the key.
- </p>
- <pre>
- var fibonacci = _.memoize(function(n) {
- return n < 2 ? n : fibonacci(n - 1) + fibonacci(n - 2);
- });
- </pre>
- <p id="delay">
- <b class="header">delay</b><code>_.delay(function, wait, [*arguments])</code>
- <br />
- Much like <b>setTimeout</b>, invokes <b>function</b> after <b>wait</b>
- milliseconds. If you pass the optional <b>arguments</b>, they will be
- forwarded on to the <b>function</b> when it is invoked.
- </p>
- <pre>
- var log = _.bind(console.log, console);
- _.delay(log, 1000, 'logged later');
- => 'logged later' // Appears after one second.
- </pre>
- <p id="defer">
- <b class="header">defer</b><code>_.defer(function, [*arguments])</code>
- <br />
- Defers invoking the <b>function</b> until the current call stack has cleared,
- similar to using <b>setTimeout</b> with a delay of 0. Useful for performing
- expensive computations or HTML rendering in chunks without blocking the UI thread
- from updating. If you pass the optional <b>arguments</b>, they will be
- forwarded on to the <b>function</b> when it is invoked.
- </p>
- <pre>
- _.defer(function(){ alert('deferred'); });
- // Returns from the function before the alert runs.
- </pre>
- <p id="throttle">
- <b class="header">throttle</b><code>_.throttle(function, wait)</code>
- <br />
- Creates and returns a new, throttled version of the passed function,
- that, when invoked repeatedly, will only actually call the original function
- at most once per every <b>wait</b>
- milliseconds. Useful for rate-limiting events that occur faster than you
- can keep up with.
- </p>
- <pre>
- var throttled = _.throttle(updatePosition, 100);
- $(window).scroll(throttled);
- </pre>
- <p id="debounce">
- <b class="header">debounce</b><code>_.debounce(function, wait, [immediate])</code>
- <br />
- Creates and returns a new debounced version of the passed function that
- will postpone its execution until after
- <b>wait</b> milliseconds have elapsed since the last time it
- was invoked. Useful for implementing behavior that should only happen
- <i>after</i> the input has stopped arriving. For example: rendering a
- preview of a Markdown comment, recalculating a layout after the window
- has stopped being resized, and so on.
- </p>
- <p>
- Pass <tt>true</tt> for the <b>immediate</b> parameter to cause
- <b>debounce</b> to trigger the function on the leading instead of the
- trailing edge of the <b>wait</b> interval. Useful in circumstances like
- preventing accidental double-clicks on a "submit" button from firing a
- second time.
- </p>
- <pre>
- var lazyLayout = _.debounce(calculateLayout, 300);
- $(window).resize(lazyLayout);
- </pre>
- <p id="once">
- <b class="header">once</b><code>_.once(function)</code>
- <br />
- Creates a version of the function that can only be called one time.
- Repeated calls to the modified function will have no effect, returning
- the value from the original call. Useful for initialization functions,
- instead of having to set a boolean flag and then check it later.
- </p>
- <pre>
- var initialize = _.once(createApplication);
- initialize();
- initialize();
- // Application is only created once.
- </pre>
- <p id="after">
- <b class="header">after</b><code>_.after(count, function)</code>
- <br />
- Creates a version of the function that will only be run after first
- being called <b>count</b> times. Useful for grouping asynchronous responses,
- where you want to be sure that all the async calls have finished, before
- proceeding.
- </p>
- <pre>
- var renderNotes = _.after(notes.length, render);
- _.each(notes, function(note) {
- note.asyncSave({success: renderNotes});
- });
- // renderNotes is run once, after all notes have saved.
- </pre>
- <p id="wrap">
- <b class="header">wrap</b><code>_.wrap(function, wrapper)</code>
- <br />
- Wraps the first <b>function</b> inside of the <b>wrapper</b> function,
- passing it as the first argument. This allows the <b>wrapper</b> to
- execute code before and after the <b>function</b> runs, adjust the arguments,
- and execute it conditionally.
- </p>
- <pre>
- var hello = function(name) { return "hello: " + name; };
- hello = _.wrap(hello, function(func) {
- return "before, " + func("moe") + ", after";
- });
- hello();
- => 'before, hello: moe, after'
- </pre>
- <p id="compose">
- <b class="header">compose</b><code>_.compose(*functions)</code>
- <br />
- Returns the composition of a list of <b>functions</b>, where each function
- consumes the return value of the function that follows. In math terms,
- composing the functions <i>f()</i>, <i>g()</i>, and <i>h()</i> produces
- <i>f(g(h()))</i>.
- </p>
- <pre>
- var greet = function(name){ return "hi: " + name; };
- var exclaim = function(statement){ return statement + "!"; };
- var welcome = _.compose(exclaim, greet);
- welcome('moe');
- => 'hi: moe!'
- </pre>
- <h2 id="objects">Object Functions</h2>
- <p id="keys">
- <b class="header">keys</b><code>_.keys(object)</code>
- <br />
- Retrieve all the names of the <b>object</b>'s properties.
- </p>
- <pre>
- _.keys({one : 1, two : 2, three : 3});
- => ["one", "two", "three"]
- </pre>
- <p id="values">
- <b class="header">values</b><code>_.values(object)</code>
- <br />
- Return all of the values of the <b>object</b>'s properties.
- </p>
- <pre>
- _.values({one : 1, two : 2, three : 3});
- => [1, 2, 3]
- </pre>
- <p id="pairs">
- <b class="header">pairs</b><code>_.pairs(object)</code>
- <br />
- Convert an object into a list of <tt>[key, value]</tt> pairs.
- </p>
- <pre>
- _.pairs({one : 1, two : 2, three : 3});
- => [[one: 1], [two: 2], [three: 3]]
- </pre>
- <p id="invert">
- <b class="header">invert</b><code>_.invert(object)</code>
- <br />
- Returns a copy of the <b>object</b> where the keys have become the values
- and the values the keys. For this to work, all of your object's values
- should be unique and string serializable.
- </p>
- <pre>
- _.invert({Moe: "Moses", Larry: "Louis", Curly: "Jerome"});
- => {Moses: "Moe", Louis: "Larry", Jerome: "Curly"};
- </pre>
- <p id="object-functions">
- <b class="header">functions</b><code>_.functions(object)</code>
- <span class="alias">Alias: <b>methods</b></span>
- <br />
- Returns a sorted list of the names of every method in an object —
- that is to say, the name of every function property of the object.
- </p>
- <pre>
- _.functions(_);
- => ["all", "any", "bind", "bindAll", "clone", "compact", "compose" ...
- </pre>
- <p id="extend">
- <b class="header">extend</b><code>_.extend(destination, *sources)</code>
- <br />
- Copy all of the properties in the <b>source</b> objects over to the
- <b>destination</b> object, and return the <b>destination</b> object.
- It's in-order, so the last source will override properties of the same
- name in previous arguments.
- </p>
- <pre>
- _.extend({name : 'moe'}, {age : 50});
- => {name : 'moe', age : 50}
- </pre>
- <p id="pick">
- <b class="header">pick</b><code>_.pick(object, *keys)</code>
- <br />
- Return a copy of the <b>object</b>, filtered to only have values for
- the whitelisted <b>keys</b> (or array of valid keys).
- </p>
- <pre>
- _.pick({name : 'moe', age: 50, userid : 'moe1'}, 'name', 'age');
- => {name : 'moe', age : 50}
- </pre>
- <p id="omit">
- <b class="header">omit</b><code>_.omit(object, *keys)</code>
- <br />
- Return a copy of the <b>object</b>, filtered to omit the blacklisted
- <b>keys</b> (or array of keys).
- </p>
- <pre>
- _.omit({name : 'moe', age : 50, userid : 'moe1'}, 'userid');
- => {name : 'moe', age : 50}
- </pre>
- <p id="defaults">
- <b class="header">defaults</b><code>_.defaults(object, *defaults)</code>
- <br />
- Fill in null and undefined properties in <b>object</b> with values from the
- <b>defaults</b> objects, and return the <b>object</b>. As soon as the
- property is filled, further defaults will have no effect.
- </p>
- <pre>
- var iceCream = {flavor : "chocolate"};
- _.defaults(iceCream, {flavor : "vanilla", sprinkles : "lots"});
- => {flavor : "chocolate", sprinkles : "lots"}
- </pre>
- <p id="clone">
- <b class="header">clone</b><code>_.clone(object)</code>
- <br />
- Create a shallow-copied clone of the <b>object</b>. Any nested objects
- or arrays will be copied by reference, not duplicated.
- </p>
- <pre>
- _.clone({name : 'moe'});
- => {name : 'moe'};
- </pre>
- <p id="tap">
- <b class="header">tap</b><code>_.tap(object, interceptor)</code>
- <br />
- Invokes <b>interceptor</b> with the <b>object</b>, and then returns <b>object</b>.
- The primary purpose of this method is to "tap into" a method chain, in order to perform operations on intermediate results within the chain.
- </p>
- <pre>
- _.chain([1,2,3,200])
- .filter(function(num) { return num % 2 == 0; })
- .tap(alert)
- .map(function(num) { return num * num })
- .value();
- => // [2, 200] (alerted)
- => [4, 40000]
- </pre>
- <p id="has">
- <b class="header">has</b><code>_.has(object, key)</code>
- <br />
- Does the object contain the given key? Identical to
- <tt>object.hasOwnProperty(key)</tt>, but uses a safe reference to the
- <tt>hasOwnProperty</tt> function, in case it's been
- <a href="http://www.devthought.com/2012/01/18/an-object-is-not-a-hash/">overridden accidentally</a>.
- </p>
- <pre>
- _.has({a: 1, b: 2, c: 3}, "b");
- => true
- </pre>
- <p id="isEqual">
- <b class="header">isEqual</b><code>_.isEqual(object, other)</code>
- <br />
- Performs an optimized deep comparison between the two objects, to determine
- if they should be considered equal.
- </p>
- <pre>
- var moe = {name : 'moe', luckyNumbers : [13, 27, 34]};
- var clone = {name : 'moe', luckyNumbers : [13, 27, 34]};
- moe == clone;
- => false
- _.isEqual(moe, clone);
- => true
- </pre>
- <p id="isEmpty">
- <b class="header">isEmpty</b><code>_.isEmpty(object)</code>
- <br />
- Returns <i>true</i> if <b>object</b> contains no values.
- </p>
- <pre>
- _.isEmpty([1, 2, 3]);
- => false
- _.isEmpty({});
- => true
- </pre>
- <p id="isElement">
- <b class="header">isElement</b><code>_.isElement(object)</code>
- <br />
- Returns <i>true</i> if <b>object</b> is a DOM element.
- </p>
- <pre>
- _.isElement(jQuery('body')[0]);
- => true
- </pre>
- <p id="isArray">
- <b class="header">isArray</b><code>_.isArray(object)</code>
- <br />
- Returns <i>true</i> if <b>object</b> is an Array.
- </p>
- <pre>
- (function(){ return _.isArray(arguments); })();
- => false
- _.isArray([1,2,3]);
- => true
- </pre>
- <p id="isObject">
- <b class="header">isObject</b><code>_.isObject(value)</code>
- <br />
- Returns <i>true</i> if <b>value</b> is an Object. Note that JavaScript
- arrays and functions are objects, while (normal) strings and numbers are not.
- </p>
- <pre>
- _.isObject({});
- => true
- _.isObject(1);
- => false
- </pre>
- <p id="isArguments">
- <b class="header">isArguments</b><code>_.isArguments(object)</code>
- <br />
- Returns <i>true</i> if <b>object</b> is an Arguments object.
- </p>
- <pre>
- (function(){ return _.isArguments(arguments); })(1, 2, 3);
- => true
- _.isArguments([1,2,3]);
- => false
- </pre>
- <p id="isFunction">
- <b class="header">isFunction</b><code>_.isFunction(object)</code>
- <br />
- Returns <i>true</i> if <b>object</b> is a Function.
- </p>
- <pre>
- _.isFunction(alert);
- => true
- </pre>
- <p id="isString">
- <b class="header">isString</b><code>_.isString(object)</code>
- <br />
- Returns <i>true</i> if <b>object</b> is a String.
- </p>
- <pre>
- _.isString("moe");
- => true
- </pre>
- <p id="isNumber">
- <b class="header">isNumber</b><code>_.isNumber(object)</code>
- <br />
- Returns <i>true</i> if <b>object</b> is a Number (including <tt>NaN</tt>).
- </p>
- <pre>
- _.isNumber(8.4 * 5);
- => true
- </pre>
- <p id="isFinite">
- <b class="header">isFinite</b><code>_.isFinite(object)</code>
- <br />
- Returns <i>true</i> if <b>object</b> is a finite Number.
- </p>
- <pre>
- _.isFinite(-101);
- => true
- _.isFinite(-Infinity);
- => false
- </pre>
- <p id="isBoolean">
- <b class="header">isBoolean</b><code>_.isBoolean(object)</code>
- <br />
- Returns <i>true</i> if <b>object</b> is either <i>true</i> or <i>false</i>.
- </p>
- <pre>
- _.isBoolean(null);
- => false
- </pre>
- <p id="isDate">
- <b class="header">isDate</b><code>_.isDate(object)</code>
- <br />
- Returns <i>true</i> if <b>object</b> is a Date.
- </p>
- <pre>
- _.isDate(new Date());
- => true
- </pre>
- <p id="isRegExp">
- <b class="header">isRegExp</b><code>_.isRegExp(object)</code>
- <br />
- Returns <i>true</i> if <b>object</b> is a RegExp.
- </p>
- <pre>
- _.isRegExp(/moe/);
- => true
- </pre>
- <p id="isNaN">
- <b class="header">isNaN</b><code>_.isNaN(object)</code>
- <br />
- Returns <i>true</i> if <b>object</b> is <i>NaN</i>.<br /> Note: this is not
- the same as the native <b>isNaN</b> function, which will also return
- true if the variable is <i>undefined</i>.
- </p>
- <pre>
- _.isNaN(NaN);
- => true
- isNaN(undefined);
- => true
- _.isNaN(undefined);
- => false
- </pre>
- <p id="isNull">
- <b class="header">isNull</b><code>_.isNull(object)</code>
- <br />
- Returns <i>true</i> if the value of <b>object</b> is <i>null</i>.
- </p>
- <pre>
- _.isNull(null);
- => true
- _.isNull(undefined);
- => false
- </pre>
- <p id="isUndefined">
- <b class="header">isUndefined</b><code>_.isUndefined(value)</code>
- <br />
- Returns <i>true</i> if <b>value</b> is <i>undefined</i>.
- </p>
- <pre>
- _.isUndefined(window.missingVariable);
- => true
- </pre>
- <h2 id="utility">Utility Functions</h2>
- <p id="noConflict">
- <b class="header">noConflict</b><code>_.noConflict()</code>
- <br />
- Give control of the "_" variable back to its previous owner. Returns
- a reference to the <b>Underscore</b> object.
- </p>
- <pre>
- var underscore = _.noConflict();</pre>
- <p id="identity">
- <b class="header">identity</b><code>_.identity(value)</code>
- <br />
- Returns the same value that is used as the argument. In math:
- <tt>f(x) = x</tt><br />
- This function looks useless, but is used throughout Underscore as
- a default iterator.
- </p>
- <pre>
- var moe = {name : 'moe'};
- moe === _.identity(moe);
- => true</pre>
- <p id="times">
- <b class="header">times</b><code>_.times(n, iterator, [context])</code>
- <br />
- Invokes the given iterator function <b>n</b> times. Each invocation of
- <b>iterator</b> is called with an <tt>index</tt> argument.
- </p>
- <pre>
- _(3).times(function(n){ genie.grantWishNumber(n); });</pre>
- <p id="random">
- <b class="header">random</b><code>_.random(min, max)</code>
- <br />
- Returns a random integer between <b>min</b> and <b>max</b>, inclusive.
- If you only pass one argument, it will return a number between <tt>0</tt>
- and that number.
- </p>
- <pre>
- _.random(0, 100);
- => 42</pre>
- <p id="mixin">
- <b class="header">mixin</b><code>_.mixin(object)</code>
- <br />
- Allows you to extend Underscore with your own utility functions. Pass
- a hash of <tt>{name: function}</tt> definitions to have your functions
- added to the Underscore object, as well as the OOP wrapper.
- </p>
- <pre>
- _.mixin({
- capitalize : function(string) {
- return string.charAt(0).toUpperCase() + string.substring(1).toLowerCase();
- }
- });
- _("fabio").capitalize();
- => "Fabio"
- </pre>
- <p id="uniqueId">
- <b class="header">uniqueId</b><code>_.uniqueId([prefix])</code>
- <br />
- Generate a globally-unique id for client-side models or DOM elements
- that need one. If <b>prefix</b> is passed, the id will be appended to it.
- Without <b>prefix</b>, returns an integer.
- </p>
- <pre>
- _.uniqueId('contact_');
- => 'contact_104'</pre>
- <p id="escape">
- <b class="header">escape</b><code>_.escape(string)</code>
- <br />
- Escapes a string for insertion into HTML, replacing
- <tt>&</tt>, <tt><</tt>, <tt>></tt>, <tt>"</tt>, <tt>'</tt>, and <tt>/</tt> characters.
- </p>
- <pre>
- _.escape('Curly, Larry & Moe');
- => "Curly, Larry &amp; Moe"</pre>
- <p id="result">
- <b class="header">result</b><code>_.result(object, property)</code>
- <br />
- If the value of the named property is a function then invoke it; otherwise, return it.
- </p>
- <pre>
- var object = {cheese: 'crumpets', stuff: function(){ return 'nonsense'; }};
- _.result(object, 'cheese');
- => "crumpets"
- _.result(object, 'stuff');
- => "nonsense"</pre>
- <p id="template">
- <b class="header">template</b><code>_.template(templateString, [data], [settings])</code>
- <br />
- Compiles JavaScript templates into functions that can be evaluated
- for rendering. Useful for rendering complicated bits of HTML from JSON
- data sources. Template functions can both interpolate variables, using
- <tt><%= … %></tt>, as well as execute arbitrary JavaScript code, with
- <tt><% … %></tt>. If you wish to interpolate a value, and have
- it be HTML-escaped, use <tt><%- … %></tt> When you evaluate a template function, pass in a
- <b>data</b> object that has properties corresponding to the template's free
- variables. If you're writing a one-off, you can pass the <b>data</b>
- object as the second parameter to <b>template</b> in order to render
- immediately instead of returning a template function. The <b>settings</b> argument
- should be a hash containing any <tt>_.templateSettings</tt> that should be overridden.
- </p>
- <pre>
- var compiled = _.template("hello: <%= name %>");
- compiled({name : 'moe'});
- => "hello: moe"
- var list = "<% _.each(people, function(name) { %> <li><%= name %></li> <% }); %>";
- _.template(list, {people : ['moe', 'curly', 'larry']});
- => "<li>moe</li><li>curly</li><li>larry</li>"
- var template = _.template("<b><%- value %></b>");
- template({value : '<script>'});
- => "<b>&lt;script&gt;</b>"</pre>
- <p>
- You can also use <tt>print</tt> from within JavaScript code. This is
- sometimes more convenient than using <tt><%= ... %></tt>.
- </p>
- <pre>
- var compiled = _.template("<% print('Hello ' + epithet); %>");
- compiled({epithet: "stooge"});
- => "Hello stooge."</pre>
- <p>
- If ERB-style delimiters aren't your cup of tea, you can change Underscore's
- template settings to use different symbols to set off interpolated code.
- Define an <b>interpolate</b> regex to match expressions that should be
- interpolated verbatim, an <b>escape</b> regex to match expressions that should
- be inserted after being HTML escaped, and an <b>evaluate</b> regex to match
- expressions that should be evaluated without insertion into the resulting
- string. You may define or omit any combination of the three.
- For example, to perform
- <a href="http://github.com/janl/mustache.js#readme">Mustache.js</a>
- style templating:
- </p>
- <pre>
- _.templateSettings = {
- interpolate : /\{\{(.+?)\}\}/g
- };
- var template = _.template("Hello {{ name }}!");
- template({name : "Mustache"});
- => "Hello Mustache!"</pre>
- <p>
- By default, <b>template</b> places the values from your data in the local scope
- via the <tt>with</tt> statement. However, you can specify a single variable name
- with the <b>variable</b> setting. This can significantly improve the speed
- at which a template is able to render.
- </p>
- <pre>
- _.template("Using 'with': <%= data.answer %>", {answer: 'no'}, {variable: 'data'});
- => "Using 'with': no"</pre>
- <p>
- Precompiling your templates can be a big help when debugging errors you can't
- reproduce. This is because precompiled templates can provide line numbers and
- a stack trace, something that is not possible when compiling templates on the client.
- The <b>source</b> property is available on the compiled template
- function for easy precompilation.
- </p>
- <pre><script>
- JST.project = <%= _.template(jstText).source %>;
- </script></pre>
- <h2 id="chaining">Chaining</h2>
- <p>
- You can use Underscore in either an object-oriented or a functional style,
- depending on your preference. The following two lines of code are
- identical ways to double a list of numbers.
- </p>
- <pre>
- _.map([1, 2, 3], function(n){ return n * 2; });
- _([1, 2, 3]).map(function(n){ return n * 2; });</pre>
- <p>
- Calling <tt>chain</tt> will cause all future method calls to return
- wrapped objects. When you've finished the computation, use
- <tt>value</tt> to retrieve the final value. Here's an example of chaining
- together a <b>map/flatten/reduce</b>, in order to get the word count of
- every word in a song.
- </p>
- <pre>
- var lyrics = [
- {line : 1, words : "I'm a lumberjack and I'm okay"},
- {line : 2, words : "I sleep all night and I work all day"},
- {line : 3, words : "He's a lumberjack and he's okay"},
- {line : 4, words : "He sleeps all night and he works all day"}
- ];
- _.chain(lyrics)
- .map(function(line) { return line.words.split(' '); })
- .flatten()
- .reduce(function(counts, word) {
- counts[word] = (counts[word] || 0) + 1;
- return counts;
- }, {}).value();
- => {lumberjack : 2, all : 4, night : 2 ... }</pre>
- <p>
- In addition, the
- <a href="https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Array/prototype">Array prototype's methods</a>
- are proxied through the chained Underscore object, so you can slip a
- <tt>reverse</tt> or a <tt>push</tt> into your chain, and continue to
- modify the array.
- </p>
- <p id="chain">
- <b class="header">chain</b><code>_.chain(obj)</code>
- <br />
- Returns a wrapped object. Calling methods on this object will continue
- to return wrapped objects until <tt>value</tt> is used.
- </p>
- <pre>
- var stooges = [{name : 'curly', age : 25}, {name : 'moe', age : 21}, {name : 'larry', age : 23}];
- var youngest = _.chain(stooges)
- .sortBy(function(stooge){ return stooge.age; })
- .map(function(stooge){ return stooge.name + ' is ' + stooge.age; })
- .first()
- .value();
- => "moe is 21"
- </pre>
- <p id="value">
- <b class="header">value</b><code>_(obj).value()</code>
- <br />
- Extracts the value of a wrapped object.
- </p>
- <pre>
- _([1, 2, 3]).value();
- => [1, 2, 3]
- </pre>
- <h2 id="links">Links & Suggested Reading</h2>
- <p>
- The Underscore documentation is also available in
- <a href="http://learning.github.com/underscore/">Simplified Chinese</a>.
- </p>
- <p>
- <a href="http://mirven.github.com/underscore.lua/">Underscore.lua</a>,
- a Lua port of the functions that are applicable in both languages.
- Includes OOP-wrapping and chaining.
- (<a href="http://github.com/mirven/underscore.lua">source</a>)
- </p>
- <p>
- <a href="http://underscorem.org">Underscore.m</a>, an Objective-C port
- of many of the Underscore.js functions, using a syntax that encourages
- chaining.
- (<a href="https://github.com/robb/Underscore.m">source</a>)
- </p>
- <p>
- <a href="http://kmalakoff.github.com/_.m/">_.m</a>, an alternative
- Objective-C port that tries to stick a little closer to the original
- Underscore.js API.
- (<a href="https://github.com/kmalakoff/_.m">source</a>)
- </p>
- <p>
- <a href="http://brianhaveri.github.com/Underscore.php/">Underscore.php</a>,
- a PHP port of the functions that are applicable in both languages.
- Includes OOP-wrapping and chaining.
- (<a href="http://github.com/brianhaveri/Underscore.php">source</a>)
- </p>
- <p>
- <a href="http://vti.github.com/underscore-perl/">Underscore-perl</a>,
- a Perl port of many of the Underscore.js functions,
- aimed at on Perl hashes and arrays.
- (<a href="https://github.com/vti/underscore-perl/">source</a>)
- </p>
- <p>
- <a href="http://russplaysguitar.github.com/UnderscoreCF/">Underscore.cfc</a>,
- a Coldfusion port of many of the Underscore.js functions.
- (<a href="https://github.com/russplaysguitar/underscorecf">source</a>)
- </p>
- <p>
- <a href="https://github.com/edtsech/underscore.string">Underscore.string</a>,
- an Underscore extension that adds functions for string-manipulation:
- <tt>trim</tt>, <tt>startsWith</tt>, <tt>contains</tt>, <tt>capitalize</tt>,
- <tt>reverse</tt>, <tt>sprintf</tt>, and more.
- </p>
- <p>
- Ruby's <a href="http://ruby-doc.org/core/classes/Enumerable.html">Enumerable</a> module.
- </p>
- <p>
- <a href="http://www.prototypejs.org/">Prototype.js</a>, which provides
- JavaScript with collection functions in the manner closest to Ruby's Enumerable.
- </p>
- <p>
- Oliver Steele's
- <a href="http://osteele.com/sources/javascript/functional/">Functional JavaScript</a>,
- which includes comprehensive higher-order function support as well as string lambdas.
- </p>
- <p>
- Michael Aufreiter's <a href="http://github.com/michael/data">Data.js</a>,
- a data manipulation + persistence library for JavaScript.
- </p>
- <p>
- Python's <a href="http://docs.python.org/library/itertools.html">itertools</a>.
- </p>
- <h2 id="changelog">Change Log</h2>
-
- <p>
- <b class="header">1.4.0</b> — <small><i>Sept. 27, 2012</i></small> — <a href="https://github.com/documentcloud/backbone/compare/1.3.3...1.4.0">Diff</a><br />
- <ul>
- <li>
- Added a <tt>pairs</tt> function, for turning a JavaScript object
- into <tt>[key, value]</tt> pairs ... as well as an <tt>object</tt>
- function, for converting an array of <tt>[key, value]</tt> pairs
- into an object.
- </li>
- <li>
- Added a <tt>countBy</tt> function, for counting the number of objects
- in a list that match a certain criteria.
- </li>
- <li>
- Added an <tt>invert</tt> function, for performing a simple inversion
- of the keys and values in an object.
- </li>
- <li>
- Added a <tt>where</tt> function, for easy cases of filtering a list
- for objects with specific values.
- </li>
- <li>
- Added an <tt>omit</tt> function, for filtering an object to remove
- certain keys.
- </li>
- <li>
- Added a <tt>random</tt> function, to return a random number in a
- given range.
- </li>
- <li>
- <tt>_.debounce</tt>'d functions now return their last updated value,
- just like <tt>_.throttle</tt>'d functions.
- </li>
- <li>
- The <tt>sortBy</tt> function now runs a stable sort algorithm.
- </li>
- <li>
- Added the optional <tt>fromIndex</tt> option to <tt>indexOf</tt> and
- <tt>lastIndexOf</tt>.
- </li>
- <li>
- "Sparse" arrays are no longer supported in Underscore iteration
- functions. Use a <tt>for</tt> instead (or better yet, an object).
- </li>
- <li>
- The <tt>min</tt> and <tt>max</tt> functions may now be called on
- <i>very</i> large arrays.
- </li>
- <li>
- Interpolation in templates now represents <tt>null</tt> and
- <tt>undefined</tt> as the empty string.
- </li>
- <li>
- A number of edge-cases fixes and tweaks, which you can spot in the
- <a href="https://github.com/documentcloud/backbone/compare/1.3.3...1.4.0">diff</a>.
- Depending on how you're using Underscore, <b>1.4.0</b> may be more
- backwards-incompatible than usual — please test when you upgrade.
- </li>
- </ul>
- </p>
- <p>
- <b class="header">1.3.3</b> — <small><i>April 10, 2012</i></small><br />
- <ul>
- <li>
- Many improvements to <tt>_.template</tt>, which now provides the
- <tt>source</tt> of the template function as a property, for potentially
- even more efficient pre-compilation on the server-side. You may now
- also set the <tt>variable</tt> option when creating a template,
- which will cause your passed-in data to be made available under the
- variable you named, instead of using a <tt>with</tt> statement —
- significantly improving the speed of rendering the template.
- </li>
- <li>
- Added the <tt>pick</tt> function, which allows you to filter an
- object literal with a whitelist of allowed property names.
- </li>
- <li>
- Added the <tt>result</tt> function, for convenience when working
- with APIs that allow either functions or raw properties.
- </li>
- <li>
- Added the <tt>isFinite</tt> function, because sometimes knowing that
- a value is a number just ain't quite enough.
- </li>
- <li>
- The <tt>sortBy</tt> function may now also be passed the string name
- of a property to use as the sort order on each object.
- </li>
- <li>
- Fixed <tt>uniq</tt> to work with sparse arrays.
- </li>
- <li>
- The <tt>difference</tt> function now performs a shallow flatten
- instead of a deep one when computing array differences.
- </li>
- <li>
- The <tt>debounce</tt> function now takes an <tt>immediate</tt>
- parameter, which will cause the callback to fire on the leading
- instead of the trailing edge.
- </li>
- </ul>
- </p>
- <p>
- <b class="header">1.3.1</b> — <small><i>Jan. 23, 2012</i></small><br />
- <ul>
- <li>
- Added an <tt>_.has</tt> function, as a safer way to use <tt>hasOwnProperty</tt>.
- </li>
- <li>
- Added <tt>_.collect</tt> as an alias for <tt>_.map</tt>. Smalltalkers, rejoice.
- </li>
- <li>
- Reverted an old change so that <tt>_.extend</tt> will correctly copy
- over keys with undefined values again.
- </li>
- <li>
- Bugfix to stop escaping slashes within interpolations in <tt>_.template</tt>.
- </li>
- </ul>
- </p>
- <p>
- <b class="header">1.3.0</b> — <small><i>Jan. 11, 2012</i></small><br />
- <ul>
- <li>
- Removed AMD (RequireJS) support from Underscore. If you'd like to use
- Underscore with RequireJS, you can load it as a normal script, wrap
- or patch your copy, or download a forked version.
- </li>
- </ul>
- </p>
- <p>
- <b class="header">1.2.4</b> — <small><i>Jan. 4, 2012</i></small><br />
- <ul>
- <li>
- You now can (and probably should, as it's simpler)
- write <tt>_.chain(list)</tt>
- instead of <tt>_(list).chain()</tt>.
- </li>
- <li>
- Fix for escaped characters in Underscore templates, and for supporting
- customizations of <tt>_.templateSettings</tt> that only define one or
- two of the required regexes.
- </li>
- <li>
- Fix for passing an array as the first argument to an <tt>_.wrap</tt>'d function.
- </li>
- <li>
- Improved compatibility with ClojureScript, which adds a <tt>call</tt>
- function to <tt>String.prototype</tt>.
- </li>
- </ul>
- </p>
- <p>
- <b class="header">1.2.3</b> — <small><i>Dec. 7, 2011</i></small><br />
- <ul>
- <li>
- Dynamic scope is now preserved for compiled <tt>_.template</tt> functions,
- so you can use the value of <tt>this</tt> if you like.
- </li>
- <li>
- Sparse array support of <tt>_.indexOf</tt>, <tt>_.lastIndexOf</tt>.
- </li>
- <li>
- Both <tt>_.reduce</tt> and <tt>_.reduceRight</tt> can now be passed an
- explicitly <tt>undefined</tt> value. (There's no reason why you'd
- want to do this.)
- </li>
- </ul>
- </p>
- <p>
- <b class="header">1.2.2</b> — <small><i>Nov. 14, 2011</i></small><br />
- <ul>
- <li>
- Continued tweaks to <tt>_.isEqual</tt> semantics. Now JS primitives are
- considered equivalent to their wrapped versions, and arrays are compared
- by their numeric properties only <small>(#351)</small>.
- </li>
- <li>
- <tt>_.escape</tt> no longer tries to be smart about not double-escaping
- already-escaped HTML entities. Now it just escapes regardless <small>(#350)</small>.
- </li>
- <li>
- In <tt>_.template</tt>, you may now leave semicolons out of evaluated
- statements if you wish: <tt><% }) %></tt> <small>(#369)</small>.
- </li>
- <li>
- <tt>_.after(callback, 0)</tt> will now trigger the callback immediately,
- making "after" easier to use with asynchronous APIs <small>(#366)</small>.
- </li>
- </ul>
- </p>
- <p>
- <b class="header">1.2.1</b> — <small><i>Oct. 24, 2011</i></small><br />
- <ul>
- <li>
- Several important bug fixes for <tt>_.isEqual</tt>, which should now
- do better on mutated Arrays, and on non-Array objects with
- <tt>length</tt> properties. <small>(#329)</small>
- </li>
- <li>
- <b>jrburke</b> contributed Underscore exporting for AMD module loaders,
- and <b>tonylukasavage</b> for Appcelerator Titanium.
- <small>(#335, #338)</small>
- </li>
- <li>
- You can now <tt>_.groupBy(list, 'property')</tt> as a shortcut for
- grouping values by a particular common property.
- </li>
- <li>
- <tt>_.throttle</tt>'d functions now fire immediately upon invocation,
- and are rate-limited thereafter <small>(#170, #266)</small>.
- </li>
- <li>
- Most of the <tt>_.is[Type]</tt> checks no longer ducktype.
- </li>
- <li>
- The <tt>_.bind</tt> function now also works on constructors, a-la
- ES5 ... but you would never want to use <tt>_.bind</tt> on a
- constructor function.
- </li>
- <li>
- <tt>_.clone</tt> no longer wraps non-object types in Objects.
- </li>
- <li>
- <tt>_.find</tt> and <tt>_.filter</tt> are now the preferred names for
- <tt>_.detect</tt> and <tt>_.select</tt>.
- </li>
- </ul>
- </p>
- <p>
- <b class="header">1.2.0</b> — <small><i>Oct. 5, 2011</i></small><br />
- <ul>
- <li>
- The <tt>_.isEqual</tt> function now
- supports true deep equality comparisons, with checks for cyclic structures,
- thanks to Kit Cambridge.
- </li>
- <li>
- Underscore templates now support HTML escaping interpolations, using
- <tt><%- ... %></tt> syntax.
- </li>
- <li>
- Ryan Tenney contributed <tt>_.shuffle</tt>, which uses a modified
- Fisher-Yates to give you a shuffled copy of an array.
- </li>
- <li>
- <tt>_.uniq</tt> can now be passed an optional iterator, to determine by
- what criteria an object should be considered unique.
- </li>
- <li>
- <tt>_.last</tt> now takes an optional argument which will return the last
- N elements of the list.
- </li>
- <li>
- A new <tt>_.initial</tt> function was added, as a mirror of <tt>_.rest</tt>,
- which returns all the initial values of a list (except the last N).
- </li>
- </ul>
- </p>
- <p>
- <b class="header">1.1.7</b> — <small><i>July 13, 2011</i></small><br />
- Added <tt>_.groupBy</tt>, which aggregates a collection into groups of like items.
- Added <tt>_.union</tt> and <tt>_.difference</tt>, to complement the
- (re-named) <tt>_.intersection</tt>.
- Various improvements for support of sparse arrays.
- <tt>_.toArray</tt> now returns a clone, if directly passed an array.
- <tt>_.functions</tt> now also returns the names of functions that are present
- in the prototype chain.
- </p>
- <p>
- <b class="header">1.1.6</b> — <small><i>April 18, 2011</i></small><br />
- Added <tt>_.after</tt>, which will return a function that only runs after
- first being called a specified number of times.
- <tt>_.invoke</tt> can now take a direct function reference.
- <tt>_.every</tt> now requires an iterator function to be passed, which
- mirrors the ECMA5 API.
- <tt>_.extend</tt> no longer copies keys when the value is undefined.
- <tt>_.bind</tt> now errors when trying to bind an undefined value.
- </p>
- <p>
- <b class="header">1.1.5</b> — <small><i>Mar 20, 2011</i></small><br />
- Added an <tt>_.defaults</tt> function, for use merging together JS objects
- representing default options.
- Added an <tt>_.once</tt> function, for manufacturing functions that should
- only ever execute a single time.
- <tt>_.bind</tt> now delegates to the native ECMAScript 5 version,
- where available.
- <tt>_.keys</tt> now throws an error when used on non-Object values, as in
- ECMAScript 5.
- Fixed a bug with <tt>_.keys</tt> when used over sparse arrays.
- </p>
- <p>
- <b class="header">1.1.4</b> — <small><i>Jan 9, 2011</i></small><br />
- Improved compliance with ES5's Array methods when passing <tt>null</tt>
- as a value. <tt>_.wrap</tt> now correctly sets <tt>this</tt> for the
- wrapped function. <tt>_.indexOf</tt> now takes an optional flag for
- finding the insertion index in an array that is guaranteed to already
- be sorted. Avoiding the use of <tt>.callee</tt>, to allow <tt>_.isArray</tt>
- to work properly in ES5's strict mode.
- </p>
- <p>
- <b class="header">1.1.3</b> — <small><i>Dec 1, 2010</i></small><br />
- In CommonJS, Underscore may now be required with just: <br />
- <tt>var _ = require("underscore")</tt>.
- Added <tt>_.throttle</tt> and <tt>_.debounce</tt> functions.
- Removed <tt>_.breakLoop</tt>, in favor of an ECMA5-style un-<i>break</i>-able
- each implementation — this removes the try/catch, and you'll now have
- better stack traces for exceptions that are thrown within an Underscore iterator.
- Improved the <b>isType</b> family of functions for better interoperability
- with Internet Explorer host objects.
- <tt>_.template</tt> now correctly escapes backslashes in templates.
- Improved <tt>_.reduce</tt> compatibility with the ECMA5 version:
- if you don't pass an initial value, the first item in the collection is used.
- <tt>_.each</tt> no longer returns the iterated collection, for improved
- consistency with ES5's <tt>forEach</tt>.
- </p>
- <p>
- <b class="header">1.1.2</b><br />
- Fixed <tt>_.contains</tt>, which was mistakenly pointing at
- <tt>_.intersect</tt> instead of <tt>_.include</tt>, like it should
- have been. Added <tt>_.unique</tt> as an alias for <tt>_.uniq</tt>.
- </p>
- <p>
- <b class="header">1.1.1</b><br />
- Improved the speed of <tt>_.template</tt>, and its handling of multiline
- interpolations. Ryan Tenney contributed optimizations to many Underscore
- functions. An annotated version of the source code is now available.
- </p>
- <p>
- <b class="header">1.1.0</b><br />
- The method signature of <tt>_.reduce</tt> has been changed to match
- the ECMAScript 5 signature, instead of the Ruby/Prototype.js version.
- This is a backwards-incompatible change. <tt>_.template</tt> may now be
- called with no arguments, and preserves whitespace. <tt>_.contains</tt>
- is a new alias for <tt>_.include</tt>.
- </p>
- <p>
- <b class="header">1.0.4</b><br />
- <a href="http://themoell.com/">Andri Möll</a> contributed the <tt>_.memoize</tt>
- function, which can be used to speed up expensive repeated computations
- by caching the results.
- </p>
- <p>
- <b class="header">1.0.3</b><br />
- Patch that makes <tt>_.isEqual</tt> return <tt>false</tt> if any property
- of the compared object has a <tt>NaN</tt> value. Technically the correct
- thing to do, but of questionable semantics. Watch out for NaN comparisons.
- </p>
- <p>
- <b class="header">1.0.2</b><br />
- Fixes <tt>_.isArguments</tt> in recent versions of Opera, which have
- arguments objects as real Arrays.
- </p>
- <p>
- <b class="header">1.0.1</b><br />
- Bugfix for <tt>_.isEqual</tt>, when comparing two objects with the same
- number of undefined keys, but with different names.
- </p>
- <p>
- <b class="header">1.0.0</b><br />
- Things have been stable for many months now, so Underscore is now
- considered to be out of beta, at <b>1.0</b>. Improvements since <b>0.6</b>
- include <tt>_.isBoolean</tt>, and the ability to have <tt>_.extend</tt>
- take multiple source objects.
- </p>
- <p>
- <b class="header">0.6.0</b><br />
- Major release. Incorporates a number of
- <a href="http://github.com/ratbeard">Mile Frawley's</a> refactors for
- safer duck-typing on collection functions, and cleaner internals. A new
- <tt>_.mixin</tt> method that allows you to extend Underscore with utility
- functions of your own. Added <tt>_.times</tt>, which works the same as in
- Ruby or Prototype.js. Native support for ECMAScript 5's <tt>Array.isArray</tt>,
- and <tt>Object.keys</tt>.
- </p>
- <p>
- <b class="header">0.5.8</b><br />
- Fixed Underscore's collection functions to work on
- <a href="https://developer.mozilla.org/En/DOM/NodeList">NodeLists</a> and
- <a href="https://developer.mozilla.org/En/DOM/HTMLCollection">HTMLCollections</a>
- once more, thanks to
- <a href="http://github.com/jmtulloss">Justin Tulloss</a>.
- </p>
- <p>
- <b class="header">0.5.7</b><br />
- A safer implementation of <tt>_.isArguments</tt>, and a
- faster <tt>_.isNumber</tt>,<br />thanks to
- <a href="http://jedschmidt.com/">Jed Schmidt</a>.
- </p>
- <p>
- <b class="header">0.5.6</b><br />
- Customizable delimiters for <tt>_.template</tt>, contributed by
- <a href="http://github.com/iamnoah">Noah Sloan</a>.
- </p>
- <p>
- <b class="header">0.5.5</b><br />
- Fix for a bug in MobileSafari's OOP-wrapper, with the arguments object.
- </p>
- <p>
- <b class="header">0.5.4</b><br />
- Fix for multiple single quotes within a template string for
- <tt>_.template</tt>. See:
- <a href="http://www.west-wind.com/Weblog/posts/509108.aspx">Rick Strahl's blog post</a>.
- </p>
- <p>
- <b class="header">0.5.2</b><br />
- New implementations of <tt>isArray</tt>, <tt>isDate</tt>, <tt>isFunction</tt>,
- <tt>isNumber</tt>, <tt>isRegExp</tt>, and <tt>isString</tt>, thanks to
- a suggestion from
- <a href="http://www.broofa.com/">Robert Kieffer</a>.
- Instead of doing <tt>Object#toString</tt>
- comparisons, they now check for expected properties, which is less safe,
- but more than an order of magnitude faster. Most other Underscore
- functions saw minor speed improvements as a result.
- <a href="http://dolzhenko.org/">Evgeniy Dolzhenko</a>
- contributed <tt>_.tap</tt>,
- <a href="http://ruby-doc.org/core-1.9/classes/Object.html#M000191">similar to Ruby 1.9's</a>,
- which is handy for injecting side effects (like logging) into chained calls.
- </p>
- <p>
- <b class="header">0.5.1</b><br />
- Added an <tt>_.isArguments</tt> function. Lots of little safety checks
- and optimizations contributed by
- <a href="http://github.com/iamnoah/">Noah Sloan</a> and
- <a href="http://themoell.com/">Andri Möll</a>.
- </p>
- <p>
- <b class="header">0.5.0</b><br />
- <b>[API Changes]</b> <tt>_.bindAll</tt> now takes the context object as
- its first parameter. If no method names are passed, all of the context
- object's methods are bound to it, enabling chaining and easier binding.
- <tt>_.functions</tt> now takes a single argument and returns the names
- of its Function properties. Calling <tt>_.functions(_)</tt> will get you
- the previous behavior.
- Added <tt>_.isRegExp</tt> so that <tt>isEqual</tt> can now test for RegExp equality.
- All of the "is" functions have been shrunk down into a single definition.
- <a href="http://github.com/grayrest/">Karl Guertin</a> contributed patches.
- </p>
- <p>
- <b class="header">0.4.7</b><br />
- Added <tt>isDate</tt>, <tt>isNaN</tt>, and <tt>isNull</tt>, for completeness.
- Optimizations for <tt>isEqual</tt> when checking equality between Arrays
- or Dates. <tt>_.keys</tt> is now <small><i><b>25%–2X</b></i></small> faster (depending on your
- browser) which speeds up the functions that rely on it, such as <tt>_.each</tt>.
- </p>
- <p>
- <b class="header">0.4.6</b><br />
- Added the <tt>range</tt> function, a port of the
- <a href="http://docs.python.org/library/functions.html#range">Python
- function of the same name</a>, for generating flexibly-numbered lists
- of integers. Original patch contributed by
- <a href="http://github.com/kylichuku">Kirill Ishanov</a>.
- </p>
- <p>
- <b class="header">0.4.5</b><br />
- Added <tt>rest</tt> for Arrays and arguments objects, and aliased
- <tt>first</tt> as <tt>head</tt>, and <tt>rest</tt> as <tt>tail</tt>,
- thanks to <a href="http://github.com/lukesutton/">Luke Sutton</a>'s patches.
- Added tests ensuring that all Underscore Array functions also work on
- <i>arguments</i> objects.
- </p>
- <p>
- <b class="header">0.4.4</b><br />
- Added <tt>isString</tt>, and <tt>isNumber</tt>, for consistency. Fixed
- <tt>_.isEqual(NaN, NaN)</tt> to return <i>true</i> (which is debatable).
- </p>
- <p>
- <b class="header">0.4.3</b><br />
- Started using the native <tt>StopIteration</tt> object in browsers that support it.
- Fixed Underscore setup for CommonJS environments.
- </p>
- <p>
- <b class="header">0.4.2</b><br />
- Renamed the unwrapping function to <tt>value</tt>, for clarity.
- </p>
- <p>
- <b class="header">0.4.1</b><br />
- Chained Underscore objects now support the Array prototype methods, so
- that you can perform the full range of operations on a wrapped array
- without having to break your chain. Added a <tt>breakLoop</tt> method
- to <b>break</b> in the middle of any Underscore iteration. Added an
- <tt>isEmpty</tt> function that works on arrays and objects.
- </p>
- <p>
- <b class="header">0.4.0</b><br />
- All Underscore functions can now be called in an object-oriented style,
- like so: <tt>_([1, 2, 3]).map(...);</tt>. Original patch provided by
- <a href="http://macournoyer.com/">Marc-André Cournoyer</a>.
- Wrapped objects can be chained through multiple
- method invocations. A <a href="#object-functions"><tt>functions</tt></a> method
- was added, providing a sorted list of all the functions in Underscore.
- </p>
- <p>
- <b class="header">0.3.3</b><br />
- Added the JavaScript 1.8 function <tt>reduceRight</tt>. Aliased it
- as <tt>foldr</tt>, and aliased <tt>reduce</tt> as <tt>foldl</tt>.
- </p>
- <p>
- <b class="header">0.3.2</b><br />
- Now runs on stock <a href="http://www.mozilla.org/rhino/">Rhino</a>
- interpreters with: <tt>load("underscore.js")</tt>.
- Added <a href="#identity"><tt>identity</tt></a> as a utility function.
- </p>
- <p>
- <b class="header">0.3.1</b><br />
- All iterators are now passed in the original collection as their third
- argument, the same as JavaScript 1.6's <b>forEach</b>. Iterating over
- objects is now called with <tt>(value, key, collection)</tt>, for details
- see <a href="#each"><tt>_.each</tt></a>.
- </p>
- <p>
- <b class="header">0.3.0</b><br />
- Added <a href="http://github.com/dmitryBaranovskiy">Dmitry Baranovskiy</a>'s
- comprehensive optimizations, merged in
- <a href="http://github.com/kriskowal/">Kris Kowal</a>'s patches to make Underscore
- <a href="http://wiki.commonjs.org/wiki/CommonJS">CommonJS</a> and
- <a href="http://narwhaljs.org/">Narwhal</a> compliant.
- </p>
- <p>
- <b class="header">0.2.0</b><br />
- Added <tt>compose</tt> and <tt>lastIndexOf</tt>, renamed <tt>inject</tt> to
- <tt>reduce</tt>, added aliases for <tt>inject</tt>, <tt>filter</tt>,
- <tt>every</tt>, <tt>some</tt>, and <tt>forEach</tt>.
- </p>
- <p>
- <b class="header">0.1.1</b><br />
- Added <tt>noConflict</tt>, so that the "Underscore" object can be assigned to
- other variables.
- </p>
- <p>
- <b class="header">0.1.0</b><br />
- Initial release of Underscore.js.
- </p>
- <p>
- <a href="http://documentcloud.org/" title="A DocumentCloud Project" style="background:none;">
- <img src="http://jashkenas.s3.amazonaws.com/images/a_documentcloud_project.png" alt="A DocumentCloud Project" />
- </a>
- </p>
- </div>
- </div>
- <!-- Include Underscore, so you can play with it in the console. -->
- <script type="text/javascript" src="underscore.js"></script>
- </body>
- </html>