Object-Oriented JavaScript - Third Edition by Antani Ved & Stefanov Stoyan

Author:Antani, Ved & Stefanov, Stoyan [Antani, Ved]
Language: eng
Format: azw3, epub
Publisher: Packt Publishing
Published: 2017-01-12T05:00:00+00:00

Using object() method

Based on the idea that objects inherit from objects, Douglas Crockford advocates the use of an object() function that accepts an object and returns a new one that has the parent as a prototype:

function object(o) { function F() {} F.prototype = o; return new F(); }

If you need access to an uber property, you can modify the object() function as follows:

function object(o) { var n; function F() {} F.prototype = o; n = new F(); n.uber = o; return n; }

Using this function is the same as using extendCopy(), you take an object such as twoDee, create a new object from it, and then proceed to augmenting the new object:

var triangle = object(twoDee); triangle.name = 'Triangle'; triangle.getArea = function () { return this.side * this.height / 2; };

The new triangle still behaves the same way:

>triangle.toString(); "Shape, 2D shape, Triangle"

This pattern is also referred to as prototypal inheritance, because you use a parent object as the prototype of a child object. It's also adopted and built upon in ES5 and called Object.create(). Here is an example:

>var square = Object.create(triangle);

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