设计模式-装饰者模式

pattern-decorator.js

// pattern-decorator.js

// ===== 1. let instance has new functions =====
function Person (name, age) {
	this.name = name;
	this.age = age;
}

Person.prototype.say = function (something) {
	console.log(this.name, 'says: ', something);
};

// now we new a person
var person1 = new Person('xiaolai-1', 18);
// let me say hi
person1.say('hi');

// then we new another person
var person2 = new Person('xiaolai-2', 19);
// let me say hello
person2.say('hello');
// and le me have the ability to run
person2.run = function (distance) {
	console.log(this.name, 'runs: ', distance, 'miles');
};
// NOTE that person2 can run but person1 can not.

// ===== 2. let instance has adding propertity =====

var person3 = new Person('xiaolai-3', 20);

function AddAge5 (person) {
	person.age += 5;
}
function AddAge10 (person) {
	person.age += 10;
}
function AddAge20 (person) {
	person.age += 20;
}

// now let my age inscrease!
AddAge5(person3);
console.log(person3.age);

AddAge10(person3);
console.log(person3.age);

AddAge20(person3);
console.log(person3.age);

装饰者模式可以简单理解为对实例进行添加属性或方法的模式

jquery 中的 $.extend 和
underscore 中的 _.extend 可以理解为装饰者模式的一种实践

var defaults = {nage}
var options = {};
var settings = {};
settings = $.extend({}, defaults, options);