How to Extend Prototypes with JavaScript

By  on  

One of the ideological sticking points of the first JavaScript framework was was extending prototypes vs. wrapping functions. Frameworks like MooTools and Prototype extended prototypes while jQuery and other smaller frameworks did not. Each had their benefits, but ultimately all these years later I still believe that the ability to extend native prototypes is a massive feature of JavaScript. Let's check out how easy it is to empower every instance of a primitive by extending prototypes!

Every JavaScript native, like Number, String, Array, Object, etc. has a prototype. Every method on a prototype is inherited by every instance of that object. For example, we can provide every `Array instance with a unique method by extending its prototype:

Array.prototype.unique = function() {
  return [...new Set(this)];
}

['1', '1', '2'].unique(); // ['1', '2']
new Array('1', '1', '2').unique(); // ['1', '2']

Note that if you can also ensure chaining capability by returning this:

['1', '1', '2'].unique().reverse(); // ['2', '1']

The biggest criticism of extending prototypes has always been name collision where the eventual specification implementation is different than the framework implementation. While I understand that argument, you can combat it with prefixing function names. Adding super powers to a native prototype so that every instance has it is so useful that I'd never tell someone not to extend a prototype. #MooToolsFTW.

Recent Features

  • By
    Responsive and Infinitely Scalable JS Animations

    Back in late 2012 it was not easy to find open source projects using requestAnimationFrame() - this is the hook that allows Javascript code to synchronize with a web browser's native paint loop. Animations using this method can run at 60 fps and deliver fantastic...

  • By
    Introducing MooTools Templated

    One major problem with creating UI components with the MooTools JavaScript framework is that there isn't a great way of allowing customization of template and ease of node creation. As of today, there are two ways of creating: new Element Madness The first way to create UI-driven...

Incredible Demos

Discussion

    Wrap your code in <pre class="{language}"></pre> tags, link to a GitHub gist, JSFiddle fiddle, or CodePen pen to embed!