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JS class extension tool for enabling easily extending prototype with multiple objects.


Helper function for setting up prototype chains for subclasses.

Largely copied out of Backbone, but modified to enable extending a prototype with multiple mixins at once.

npm install ampersand-class-extend

Your base object module might look something like this:

var extend = require('ampersand-class-extend');
// your base object 
function YourConstructor() {}
// simply attach it directly to the object constructor 
YourConstructor.extend = extend;
// export it 
module.exports = YourConstructor;

Then in a file using said constructor:

var YourConstructor = require('./your-constructor');
var mixinMethods = require('some-other-methods');
var otherMixinMethods = require('even-more-methods');
// Nowe we add some more stuff and export a modified constructor  
// (we can pass in as many other objects containing methods as we want). 
module.exports = YourConstructor.extend(mixinMethods, otherMixinMethods, {
    yetAnotherMethod: function () {
        // do something 

Now, when creating instances of the subclass, they'll have all the mixins while still passing instanceof checks for both the parent and the subclass.

Most of the credit goes to Jeremy Ashkenas and the other authors of Backbone.js.

Modified to be standalone Common JS and to allow you to pass multiple extend objects by @HenrikJoreteg.