erickj / js-base

Simple classical inheritance model for javascript based on Closure's goog.base and goog.inherits.

grail

Yet another Javascript inheritance API.

grail is a lightweight Javascript pseudo-classical inheritance model modeled after Closure library's goog.inherits and goog.base. It is designed to be used without the Closure library and free of the non-standard hack of arguments.callee.caller that doesn't work in Rhino.

Using grail

Grail may be used to setup class inheritance, call super class constructors during instantiation, and call overriden methods.

Class Inheritance

To use it pull grail.min.js into your project and use it to set up class inheritance.

/**
 * @param {string} genus
 * @constructor
 */
var Animal = function(genus) {
  this.genus = genus;
};


/**
 * {@code grail.inherit} is executed during read time to extend Dog
 * from Animal. Specifically Dog.prototype is set to an object with a
 * prototype of Animal.prototype.
 * @constructor
 * @extends {Animal}
 */
var Dog = grail.inherit(function() {
  // {@code grail.call} calls the {@code Animal} super class constructor.
  grail.call(this, Dog, 'canine');
}, Animal);

var spot = new Dog();
spot.genus; // returns 'canine'

Calling Overridden Methods

To call an overridden methods use grail.call with the instance and the method name followed by any arguments to pass.

Animal.prototype.doSomething = function(a, few, params) {
  // do stuff
  return result;
}


/** @override */
Dog.prototype.doSomething = function(a, few, more, params) {
  var superResult = grail.call(this, 'doSomething', a, few, params);
  // do more stuff
  return superResult;
}

grail is compilied with the closurecompiler and tested with jasmine.