proto-js

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Proto.js – prototypes as classes

The core idea of Proto.js is that many things become simpler in JavaScript if you make the prototype the class and not the constructor. Details: http://www.2ality.com/2011/06/prototypes-as-classes.html

Code:

// Superclass
var Person = Proto.extend({
    constructor: function (name) {
        this.name = name;
    },
    describe: function() {
        return "Person called "+this.name;
    }
});

// Subclass
var Employee = Person.extend({
    constructor: function (name, title) {
        Employee.super.constructor.call(this, name);
        this.title = title;
    },
    describe: function () {
        return Employee.super.describe.call(this)+" ("+this.title+")";
    }
});

Interaction:

var jane = Employee.new("Jane", "CTO"); // normally: new Employee(...)

> Employee.isPrototypeOf(jane) // normally: jane instanceof Employee
true

> jane.describe()
'Person called Jane (CTO)'