gistfile1.js

Function.prototype.beforeStatic = function(methodName, newFunc) {
	var oldFunc = this.prototype[methodName];
	this.prototype[methodName] = function() {
		newFunc.apply(this, arguments);
		return oldFunc.apply(this, arguments);
	};
};
Function.prototype.afterStatic = function(methodName, newFunc) {
	var oldFunc = this.prototype[methodName];
	this.prototype[methodName] = function() {
		var oldFuncResult = oldFunc.apply(this, arguments);
		var newArgsArr = Array.prototype.slice.call(arguments);
		newArgsArr.push(oldFuncResult);
		newFunc.apply(this, newArgsArr);
		return oldFuncResult;
	};
};
Function.prototype.beforeInstance = function(instance, methodName, newFunc) {
	var oldFunc = instance[methodName];
	instance[methodName] = function() {
		newFunc.apply(instance, arguments);
		return oldFunc.apply(instance, arguments);
	};
};
Function.prototype.afterInstance = function(instance, methodName, newFunc) {
	var oldFunc = instance[methodName];
	instance[methodName] = function() {
		var oldFuncResult = oldFunc.apply(instance, arguments);
		var newArgsArr = Array.prototype.slice.call(arguments);
		newArgsArr.push(oldFuncResult);
		newFunc.apply(instance, newArgsArr);
		return oldFuncResult;
	};
};
Function.prototype.beforeConstruction = function(newFunc) {
	var oldObj = this;
	var newObj = function() {
		newFunc.apply(this, arguments);
		oldObj.apply(this, arguments);
	}
	newObj.prototype = oldObj.prototype;
	return newObj;
};
Function.prototype.afterConstruction = function(newFunc) {
	var oldObj = this;
	var newObj = function() {
		oldObj.apply(this, arguments);
		newFunc.apply(this, arguments);
	}
	newObj.prototype = oldObj.prototype;
	return newObj;
};