$ yarn add global ts-node

确定API 以及 测试用例

• EventHub#on
• EventHub#off
• EventHub#emit

/src/index.ts

class EventHub {
    cache = {}
    on(eventName, fn) {
        this.cache[eventName] = this.cache[eventName] || []
        this.cache[eventName].push(fn)
    }
    emit(eventName, data?) {
        (this.cache[eventName] || []).forEach(fn => fn(data))
    }
    off(eventName, fn) {
        this.cache[eventName] = this.cache[eventName] || []
        let index = indexOf(this.cache[eventName], fn)
        if (index === -1) return
        this.cache[eventName].splice(index, 1)
    }
}
export default EventHub
/* 帮助函数indexOf */
function indexOf(array, item) {
    if (array === undefined) return -1
    let index = -1
    for (let i = 0; i < array.length; i++) {
        if (array[i] === item) {
            index = i
            break
        }
    }
    return index
}

/test/index.ts

import EventHub from '../src/index';
const test1 = (message) => {
    const eventHub = new EventHub()
    console.assert(eventHub instanceof Object === true, "eventHub 是个对象")
    console.log(message)
}
const test2 = (message) => {
    const eventHub = new EventHub()
    let called = false
    eventHub.on("xxx", (data) => {
        called = true
        console.log("男篮", data)
    })
    eventHub.emit("xxx", "迈特凯")
    setTimeout(() => {
        console.assert(called)
        console.log(message)
    }, 1000)
}
const test3 = (message) => {
    const eventHub = new EventHub()
    let called = false
    const fn = () => {
        called = true
        console.log("yyy")
    }
    eventHub.on("yyy", fn)
    eventHub.off("yyy", fn)
    eventHub.emit("yyy")
    setTimeout(() => {
        console.assert(called)
        console.log(message)
    }, 1000)
}
test1('EventHub可以创建对象')
test2('on 之后 emit会触发on的回调函数')
test3('off卸载监听')

$ ts-node test/index.ts

优化TS

/src/index.ts

class EventHub {
    private cache: { [key: string]: Array<(data?: unknown) => void> } = {}
    on(eventName: string, fn: (data?: unknown) => void) {
        this.cache[eventName] = this.cache[eventName] || []
        this.cache[eventName].push(fn)
    }
    emit(eventName: string, data?: unknown) {
        (this.cache[eventName] || []).forEach(fn => fn(data))
    }
    off(eventName: string, fn: (data?: unknown) => void) {
        this.cache[eventName] = this.cache[eventName] || []
        let index = indexOf(this.cache[eventName], fn)
        if (index === -1) return
        this.cache[eventName].splice(index, 1)
    }
}
export default EventHub
/*  */
function indexOf(array: Array<(data?: unknown) => void>, item: (data?: unknown) => void) {
    if (array === undefined) return -1
    let index = -1
    for (let i = 0; i < array.length; i++) {
        if (array[i] === item) {
            index = i
            break
        }
    }
    return index
}

/test/index.ts

import EventHub from '../src/index';
type TestCase = (message: string) => void
const test1: TestCase = (message) => {
    const eventHub = new EventHub()
    console.assert(eventHub instanceof Object === true, "eventHub 是个对象")
    console.log(message)
}
const test2: TestCase = (message) => {
    const eventHub = new EventHub()
    let called = false
    eventHub.on("xxx", (data) => {
        called = true
        console.log("男篮", data)
    })
    eventHub.emit("xxx", "迈特凯")
    setTimeout(() => {
        console.assert(called)
        console.log(message)
    }, 1000)
}
const test3: TestCase = (message) => {
    const eventHub = new EventHub()
    let called = false
    const fn = () => {
        called = true
        console.log("yyy")
    }
    eventHub.on("yyy", fn)
    eventHub.off("yyy", fn)
    eventHub.emit("yyy")
    setTimeout(() => {
        console.assert(called)
        console.log(message)
    }, 1000)
}
test1('EventHub可以创建对象')
test2('on 之后 emit会触发on的回调函数')
test3('off卸载监听')