wrap method

gistfile1.txt

/**
 * Wrap a method with extended functionality, preserving the original function
 * @param {Object} obj The context object that the method belongs to 
 * @param {String} method The name of the method to extend
 * @param {Function} func A wrapper function callback. This function is called with the same arguments
 * as the original function, except that the original function is unshifted and passed as the first 
 * argument. 
 */
function wrap(obj, method, func) {
  var proceed = obj[method];
	obj[method] = function () {
		var args = Array.prototype.slice.call(arguments);
		args.unshift(proceed);
		return func.apply(this, args);
	};
}