functional inheritance

gistfile1.txt

/**
 * method(that, name, method, _super)
 * Adds a method to the current object denoted by that and preserves
 * _super implementation (see Crockford)
 */
method = function(that, name, method, _super) {
    if(_super) {
	var m = that[name];
	_super[name] = function() {
	    return m.apply(that, arguments);
	};    
    }
    that[name] = method;    
};


var A = function(spec, my) {
  my = my || {};
  var _super = {};

  my.counter = spec.init || 10;

  // public
  var test; 
  // private
  var work;

  var that = {};

  work = function() {
    my.counter++;
    console.log('work A called');    
  };

  test = function() {
    work();
    console.log('test A called: ' + my.counter);
  };

  method(that, 'test', test, _super);

  return that;
};


var B = function(spec, my) {
  my = my || {};
  var _super = {};
  
  // public
  var test;

  var that = A(spec, my);
  
  test = function() {
    _super.test();
    console.log('test B called: ' + my.counter);    
  };

  method(that, 'test', test, _super);  

  return that;
};


ar a = A({init: 20});
a.test();

var b = B({});
b.test();

var c = B({init: 30});
c.test();