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POImplement map in javascript that supports object methods as mapped functions?
 

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    <p>I recently tried to use an implementation of map in javascript to create a bunch of items, then apply them to an objects add method.</p> <p>Firstly with a bog standard implementation of map.</p> <pre><code>var map = function (fn, a) { for (i = 0; i &lt; a.length; i++) { a[i] = fn(a[i]); } } </code></pre> <p>Setup.</p> <pre><code>var translateMenu = new Menu; var languages = [ ['Chinese' , 'zh-CN'] , ['German' , 'de'] , ['French' , 'fr'] , ['Portugese' , 'pt'] , ['Hindi' , 'hi'] ]; </code></pre> <p>And my function... (not anonymous, as it's later used when adding the translateMenu to mainMenu.)</p> <pre><code>var langItem = function (language, subMenu) { return new MenuItem(language[0], 'http://translate.google.com/translate?u=www.example.com&amp;hl=en&amp;ie=UTF-8&amp;tl=en&amp;sl=' + language[1] , "" , subMenu); } map ( langItem , languages ); </code></pre> <p>This all worked fine, I now had an array of MenuItems to throw around.</p> <p>Trying to call <code>map( Menu.add , languages )</code> would result in internal variables of Menu being undefined, and the call failing.<br> Now I'm certain this has to do with the scope of the <code>Menu.add()</code> method, so i thought if I passed in the object as well, it might work. </p> <p>I tried creating a new map function that would accept objects and functions, but had the same undefined error.</p> <pre><code>objMap (fn , obj , a) { for (i = 0; i &lt; a.length; i++) { obj.fn(a); } } objMap ( add , translateMenu , languages ); // failed </code></pre> <p>I worked around this by extending Menu with addAll() to take an array, which works fine...</p> <pre><code>Menu.prototype.addAll = function (items){ for (i = 0; i &lt; items.length; i++) { this.add(items[i]); } } translateMenu.addAll( languages ); // yay! but I want a more elegant solution. </code></pre> <p>Anyway, my question is, <strong>how could I implement map (or a similar generic function) to actually support using object methods as my mapped functions?</strong>.</p>
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