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copied!<p>Consider:</p> <pre><code>function ThingWithEvent() { var thing = {}, events = {}; function raise( key ) { if ( !events[ key ] ) { return; } for ( var i = 0; i < events[ key ].funcs.length; i++ ) events[ key ].funcs[ i ](); } thing.subscribe = function ( key, func ) { if ( !events[ key ] ) { events[ key ] = { name: key, funcs: [] }; } events[ key ].funcs.push( func ); }; thing.doSomething = function () { alert( "doing something" ); raise( "X" ); }; return thing; } </code></pre> <p>So, each instance of <code>ThingWithEvent</code> will get it's own <code>events</code> object (which is a private member of the instance because it's a local variable of the constructor). </p> <p><code>raise</code> is a nested function inside the constructor which makes it a private method of the instance.</p> <p><code>this.subscribe</code> and <code>this.doSomething</code> are "privileged" methods of the instance. They <strong>and only they</strong> can access the private members and private methods of the instance.</p> <p>Btw, I defined a explicit <code>thing</code> object which represents the new instance. I do this instead of just using <code>this</code> (which represents the new instance by default), because it enables me to identify the new instance uniquely inside the constructor even in nested functions - no <code>var self = this;</code> hack necessary.</p> <hr> <p><strong>Update:</strong><br> This would be inheritance:</p> <pre><code>function Thing() { var thing = Object.create( new EventTarget ); thing.doSomething = function () { alert( "doing something" ); this.raise( "X" ); }; return thing; } function EventTarget() { var events = {}; this.raise = function ( key ) { if ( !events[ key ] ) { return; } for ( var i = 0; i < events[ key ].funcs.length; i++ ) events[ key ].funcs[ i ](); } this.subscribe = function ( key, func ) { if ( !events[ key ] ) { events[ key ] = { name: key, funcs: [] }; } events[ key ].funcs.push( func ); }; } </code></pre> <p>Usage:</p> <pre><code>var thing = new Thing(); thing.subscribe( ... ); thing.doSomething( ... ); </code></pre>

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