class Publish {
 constructor() {
  this.listMap = {};
 }
	// 订阅
 on(key, fn) {
  this.listMap[key]
   "htmlcode">

const ob = new Publish();

// 订阅 sub1
const sub1 = ob.on('sub1', (a, b) => {
 console.log('sub1', a, b);
});

// 订阅 sub1
const sub11 = ob.on('sub1', (a, b) => {
 console.log('sub11', a, b);
});

ob.trigger('sub1', 2, 3);

// 取消订阅sub1
sub1();

// 取消订阅sub11
sub11();

// 订阅 sub3
ob.on('sub3', (a, b) => {
 console.log('sub3', a, b);
});

// 订阅 sub3
ob.on('sub3', (a, b) => {
 console.log('sub33', a, b);
});

ob.trigger('sub3', 6, 7);

// 取消订阅所有的sub3
ob.off('sub3');

// 订阅一次就自行取消订阅
ob.once('sub4', (a, b) => {
 console.log('sub4', a, b);
});

ob.trigger('sub4', 8, 9);



总结