util.inherits in coffeescript

Question

I am working on a Node.js server and I am using coffee script to develop.

How does this work on coffee script?

EventEmitter = require('events').EventEmitter

util.inherits(Connector, EventEmitter)

Is it?

EventEmitter = require('events').EventEmitter

class @Connector extends EventEmitter

I am basically trying to add emit to Connector. Something like:

this.emit('online')

It is valid, I'm referring to `inherits`. What you can do is compare the compiled code, and see if it does the same thing. — elclanrs, Jul 01 '14 at 07:29
So are you having problems? Any errors in console? I'm not sure I understand what you're asking. If you want to see if `inherits` does the same as `extends` in Coffee, compile the code, and compare it against the JavaScript version. — elclanrs, Jul 01 '14 at 07:33

score 2 · Accepted Answer · edited May 23 '17 at 12:29

Yes, extends does a similar thing as util.inherits.

Implementation of util.inherits:

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

Compilation of extends:

var __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;
};

function Connector() {
    return Connector.__super__.constructor.apply(this, arguments);
}
__extends(Connector, EventEmitter);

The differences are:

The exact name of the super property on the child constructor
util.inherits uses Object.create while extends does use an ES3-compatible version
util.inhirits makes the constructor property of the child constructor non-enumerable
extend copies "static" properties of the parent constructor onto the child constructor
The extends keyword automatically calls the super constructor if no constructor is given for the class

util.inherits in coffeescript

1 Answers1