1. 外观模式的定义

该模式就是把一些复杂的流程 封装 成一个接口供给外部用户 更简单 的使用。

class CPU {
    start() { console.log('打开CPU'); }
}
class Memory {
    start() { console.log('打开内存'); }
}
class Disk {
    start() { console.log('打开硬盘'); }
}
class Computer {
    constructor() {
        this.cpu = new CPU();
        this.memory = new Memory();
        this.disk = new Disk();
    }
    start() {
        this.cpu.start();
        this.memory.start();
        this.disk.start();
    }
}
new Computer().start();

class Sum{
    sum(a,b) {
        return a+b;
    }
}
class Minus{
    minus(a,b) {
        return a-b;
    }
}
class Multiply{
    multiply(a,b) {
        return a * b;
    }
}
class Calculator{
    constructor() {
        this.sumObj=new Sum();
        this.minusObj=new Minus();
        this.multiplyObj=new Multiply();
    }
    sum(...args) {
        this.sumObj.sum(...args);
    }
    minus(...args) {
        this.minusObj.minus(...args);
    }
    multiply(...args) {
        this.multiplyObj.multiply(...args);
    }
}
let calculator=new Calculator();
calculator.sum(1,2);
calculator.minus(1,2);
calculator.multiply(1,2);