After a bit of thought it occurred to me just how dangerous using frameworks, like Prototype, which augment built-in objects in large-scale production projects. As many avid JS developers are most likely aware, the prototype inheritance model of the language allows for the extension of virtually any object in the language, user defined or otherwise. However, this can also have severe side effects if a browser developer decides to include a method of the same name as your framework of choice added to a built-in object some years back.
Take, for example, the venerable each function. Prototype extends enumerable objects such as arrays with this function in its prototype. e.g.
var i = 0;
for(; i < this.length; i = i + 1){
f(this[i],i);
}
}
Now imagine this code is called in thousands of places in your project. Let’s also assume before extending the object prototype such a library would also check for the existence of said function as to not overwrite default behavior e.g.:
…
}
Now imagine an A-grade browser’s newest version now includes the each method on collection objects by default but with either an argument omitted, or the argument order swapped. All of the code that you had written that depended on the augmented each function instead of the built-in each function will now no longer work in that browser, and you can’t very well force users to not use the latest version of IE, Safari, Firefox, or Opera because a decision was made some years back to use a framework which augments built-in objects.
This decision may now cost many thousands of dollars, if not more. Other JS frameworks such as YUI or jQuery seem like a much more sound choice in this respect. In my opinion, YUI is probably the better of the two choices as it is far easier to pick-up and master by developers of other, not necessarily web-centric languages. Yet in the scope of this rant, both are equally more sound than using something which could very easily and most likely inevitably break a few years down the road, costing many unnecessary man-hours, and perhaps dollars, to fix.
Tags: Javascript, Programming