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POJavascript: Mozilla .watch() functionality for all properties of an object (possibly cross-browser)
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copied!<p><a href="https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Objects/Object/watch" rel="nofollow noreferrer">https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Objects/Object/watch</a></p> <p>The .watch() method does this in short: "Watches for a property to be assigned a value and runs a function when that occurs."</p> <p>Long descriptive form: "Watches for assignment to a property named prop in this object, calling handler(prop, oldval, newval) whenever prop is set and storing the return value in that property. A watchpoint can filter (or nullify) the value assignment, by returning a modified newval (or by returning oldval)."</p> <p>There is a question for getting it to work in all browsers here: <a href="https://stackoverflow.com/questions/1029241/javascript-object-watch-for-all-browsers">Object.watch() for all browsers?</a></p> <p>I am looking for something similar to that. What I'm looking for is a method I can use to fit this specification: "Watches for assignment to any property in this object and runs a function when that occurs." The main difference is that it is any property, and just any specific property.</p> <p>Can somebody create such a method or if they know such a method is already in existence, link to it? It'd be useful to have it work in all browsers (minus IE, or minus IE8 if IE9 conforms)</p> <p>Edit: For an example of what I mean, I'll show what I need it for.</p> <pre><code>var DiscreteLine = function (leftBound, length){ this.positive = []; this.negative = []; this.length = length; this.leftBound = leftBound; this.rightBound = leftBound + length if (this.leftBound < 0){ this.negative.length = (leftBound * -1) + 1; } else { this.negative.length = 0; } if (this.rightBound >= 0){ this.positive.length = rightBound + 1; } else { this.positive.length = 0; } this.watchObject = new ObjectWatcher(handler(prop, oldval, newval){ /* some stuff */ }); } </code></pre> <p>Then, when for example, if somebody did the following:</p> <pre><code>theLine = new DiscreteLine(-2, 4); theLine[-8] = 10; </code></pre> <p>The handler would call, with the arguments ("-8", undefined, 10). (What would end up happening is, is that the script would recalculate leftBound and length properties automatically (like how Arrays automatically update the length property).</p>

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