class MessageCenter {
subscribers = {}; // 记录各个订阅类型订阅者的randomKey
subscribersCallback = {}; // 记录各个订阅类型订阅者的回调
subscribe(key, callback) {
// console.log('订阅了' + key);
const randomKey = String(Math.random());
if (!this.subscribers[key]) {
this.subscribers[key] = [randomKey];
} else this.subscribers[key].push(randomKey);
if (!this.subscribersCallback[key]) this.subscribersCallback[key] = {};
this.subscribersCallback[key][randomKey] = callback;
// console.log('当前订阅者：', this.subscribers, this.subscribersCallback);
return () => this.unsubscribe(key, randomKey)
}
unsubscribe(key, randomKey) {
// console.log('取消订阅了' + key);
if (!this.subscribers[key]) return;
const deleteIndex = this.subscribers[key].findIndex(item => item === randomKey);
if (deleteIndex === -1) return;
this.subscribers[key].splice(deleteIndex, 1);
delete this.subscribersCallback[key][randomKey];
// console.log('当前订阅者：', this.subscribers, this.subscribersCallback);
}
publish(key, payload) {
// console.log('收到了发布' + key);
if (!this.subscribers[key]) return;
this.subscribers[key].forEach(randomKey => {
const callback = this.subscribersCallback[key][randomKey];
if (typeof callback === 'function') {
try {
callback(payload);
}
catch (e) {
}
}
});
}
}
const messageCenter = new MessageCenter();
const a = messageCenter.subscribe('buy', (payload) => {
console.log(`a收到信息, ${ payload.name } price is ${ payload.price }`)
});
const b = messageCenter.subscribe('buy', (payload) => {
console.log(`b收到信息, ${ payload.name } price is ${ payload.price }`)
});
messageCenter.publish('buy', {
price: 100,
name: '全家桶'
});
a(); // a取消订阅
messageCenter.publish('buy', {
price: 13,
name: '一对辣翅'
});
输出
"a收到信息, 全家桶 price is 100"
"b收到信息, 全家桶 price is 100"
"b收到信息, 一对辣翅 price is 13"
