Looking for a JavaScript implementation of node's "util.inherits"

Question

I am implementing a JavaScript library that can also run on node, and I'd like to use node's API as much as possible. My objects emit events, so I found this nice library called eventemitter2, and which reimplements EventEmitter for JavaScript. Now I'd like to find the same for util.inherits. Has anybody heard about such a project ?

Answer 1

Have you tried using the Node.js implementation? (It uses Object.create, so it may or may not work on the browsers you care about). Here's the implementation, from https://github.com/joyent/node/blob/master/lib/util.js:

inherits = function(ctor, superCtor) {
  ctor.super_ = superCtor;
  ctor.prototype = Object.create(superCtor.prototype, {
    constructor: {
      value: ctor,
      enumerable: false,
      writable: true,
      configurable: true
    }
  });
};

Another method is used by CoffeeScript, which compiles

class Super
class Sub extends Super

to

var Sub, Super,
  __hasProp = {}.hasOwnProperty,
  __extends = function(child, parent) { for (var key in parent) { if (__hasProp.call(parent, key)) child[key] = parent[key]; } function ctor() { this.constructor = child; } ctor.prototype = parent.prototype; child.prototype = new ctor(); child.__super__ = parent.prototype; return child; };

Super = (function() {

  function Super() {}

  return Super;

})();

Sub = (function(_super) {

  __extends(Sub, _super);

  function Sub() {
    return Sub.__super__.constructor.apply(this, arguments);
  }

  return Sub;

})(Super);

Answer 2

You don't need to use any external library. Just use javascrit as is.

B inherits from A

B.prototype = Object.create (A.prototype);
B.prototype.constructor = B;

And inside the constructor of B:

A.call (this, params...);

If you know that javascript has a property named constructor, then avoid it, no need to hide or not enumerate it, avoid avoid avoid. No need to have a super property, simply use A.call. This is javascript, don't try to use it like any other language because you will miserably fail.