个人理解的应用场景

举个例子，比如想要创建各种类型的车的实例，车的类型有很多种,但创建每种类型车的接口定义可能是一样的，就用到了此模式

相关概念的通俗解释

1. 上述例子中接口的定义叫builder
2. 接口到每种类型的车的具体实现叫concrete builder
3. 真正用于创建车的类叫director

实现模式的思路

1.首先要定义builder的接口

2.然后各个concretebuilder类去实现这个接口

3.director中接收一个builder实例作为参数，最后返回一个一类车的实例

示例代码

function Director() {    this.construct = function (builder) {        builder.step1();        builder.step2();        return builder.get();    }}//由于js不支持接口，我个人认为其实应当typescript定义一个接口，然后下面两个类去实现这个接口function CarBuilder() {    this.car = null;    this.step1 = function () {        this.car = new Car();    };    this.step2 = function () {        this.car.addParts();    };    this.get = function () {        return this.car;    };}function TruckBuilder() {    this.truck = null;    this.step1 = function () {        this.truck = new Truck();    };    this.step2 = function () {        this.truck.addParts();    };    this.get = function () {        return this.truck;    };}function Car() {    this.doors = 0;    this.addParts = function () {        this.doors = 4;    };    this.say = function () {        log.add("I am a " + this.doors + "-door car");    };}function Truck() {    this.doors = 0;    this.addParts = function () {        this.doors = 2;    };    this.say = function () {        log.add("I am a " + this.doors + "-door truck");    };}//其他开发者使用代码段new Director().construct(new CarBuilder());