发布订阅

class Event {
    eventObj = {}
    constructor() {
        this.eventObj = {}
    }

    on(key, fn) {
        this.eventObj[key] = fn
    }

    emit(key, ...args) {
        this.eventObj[key](...args)
    }
    off (key) {
        this.eventObj[key] = null
    }
}

// 测试
const myEvent = new Event()
myEvent.on('name', () => {
    console.log('修改了name')
})

myEvent.emit('name', 'Mary')