中介者模式

比如有很多个对象，对象之间又频繁地相互访问，

class A {
    constructor() {
        this.number = 0;
    }
    setNumber(num, m) {
        this.number = num;
        if (m) {
            m.setB();
        }
    }
}

class B {
    constructor() {
        this.number = 0;
    }
    setNumber(num, m) {
        this.number = num;
        if (m) {
            m.setA(num, m);
        }
    }
}

//中介者
class Mediator {
    constructor(a, b) {
        this.a = a;
        this.b = b;
    }

    setB() {
        let number = this.a.number * 66;
        this.b.setNumber(number); //此时没有传m
    }

    setA() {
        let number = this.b.number * 88;
        this.a.setNumber(number); //此时没有传m
    }
}

let a = new A();
let b = new B();
let m = new Mediator(a, b);

a.setNumber(100, m);
console.log(a.number, b.number);
// 100 6600

b.setNumber(100, m);
console.log(a.number, b.number);
// 8800 100

以上 A 和 B之间都不能相互访问，只能通过中介者来访问。