create

The missing Native.create() functions that ECMA forgot.

create is a module for node.js (and someday the browser too) that implements the "missing" .create() functions on the rest of the native data types in JavaScript.

ECMAScript version 5 introduced Object.create(). So why not Array.create()? Or Function.create()? Well that's exactly what this module adds functionality for.

In essense, this gives you a clean interface for subclassing the native classes, and also gets all the same benefits that Object.create() gives you, like setting the prototype at creation-time, and being able to pass an object descriptor in to define additional properties.

When you require the module, you invoke it as a function and pass in any native classes you want extended with a .create() function. This can be done with any of the native types.

Installation

Install with npm:

$ npm install create

Example

Let's make a subclass of Array, that includes a remove() function:

require('create')(Array)

// `Array2` is the prototype of our subclass
var Array2 = Object.create(Array.prototype)

// remove() impl from http://ejohn.org/blog/javascript-array-remove
Array2.remove = function (from, to) {
  var rest = this.slice((to || from) + 1 || this.length);
  this.length = from < 0 ? this.length + from : from;
  return this.push.apply(this, rest);
}


// now we can create an instance of Array2
var a = Array.create(Array2)

// add some items to it
a.push(1, 2, 3)
a.push('foo', 'bar')
// [1, 2, 3, 'foo', 'bar']

a.remove(1)
// [1, 3, 'foo', 'bar']

Limitations

This module depends on the writability of the __proto__ property on objects. From a browser standpoint, this module will only work in browsers where that is true (__proto__ MAY be changed). In node this will always work.