<ul id="couq4"></ul>

一道很有意思的面試題

curlyCheng 發(fā)布于2019-08-26 18:18 / 549人閱讀

摘要：實(shí)現(xiàn)下面這道題中的函數(shù)這里等待了原型寫法維護(hù)一個(gè)數(shù)組，異步就函數(shù)，不是異步就字符串寫法維護(hù)一個(gè)隊(duì)列數(shù)組，里面全部是構(gòu)造函數(shù)，第一個(gè)參數(shù)代碼是否異步，第二個(gè)是比較數(shù)組每一個(gè)都是構(gòu)造函數(shù)有點(diǎn)浪費(fèi)空間

實(shí)現(xiàn)下面這道題中的machine函數(shù)

function machine() {
    
}
machine("ygy").execute() 
// start ygy
machine("ygy").do("eat").execute(); 
// start ygy
// ygy eat
machine("ygy").wait(5).do("eat").execute();
// start ygy
// wait 5s（這里等待了5s）
// ygy eat
machine("ygy").waitFirst(5).do("eat").execute();
// wait 5s
// start ygy
// ygy eat

原型寫法

維護(hù)一個(gè)數(shù)組，異步就push函數(shù)，不是異步就push字符串

function machine(name) {
    if(!(this instanceof machine)){
        return new machine(name)
    }  
    this.name = name
    this.logs = []
    this.logs.push(`start ${name}`)
}
machine.defer = function(time){
    const times = time
    return function(){
        console.log(`wait ${times}s`)
          return new Promise((resolve)=>{
            setTimeout(()=>{resolve()},times*1000)
        })
    }
}
machine.prototype.execute = async function(){
    const logs = this.logs
    if(logs.length > 0){
         for(let i=0; i
es6寫法
維護(hù)一個(gè)queue隊(duì)列數(shù)組，里面全部是構(gòu)造函數(shù)，第一個(gè)參數(shù)代碼是否異步，第二個(gè)是callback
function machine(name) {
    return new Action(name)
}


const defer = (time, callback) => {
    return new Promise((resolve) => {
        setTimeout(() => {
            resolve(callback())
        }, time * 1000)
    })
}
class QueueItem {
    constructor(defer, callback) {
        this.defer = defer;
        this.callback = callback;
    }
}
class Action {
    queue = []
    constructor(name) {
        this.name = name;
        this.queue.push(new QueueItem(0, () => console.log(`start ${this.name}`)))
    }
    do(eat) {
        this.queue.push(new QueueItem(0, () => console.log(`${this.name} ${eat}`)))
        return this;
    }
    wait(time) {
        this.queue.push(new QueueItem(time, () => console.log(`wait ${time}s`)))
        return this;
    }
    waitFirst(time) {
        this.queue.unshift(new QueueItem(time, () => console.log(`wait ${time}s`)))
        return this;
    }
    async execute() {
        while(this.queue.length > 0) {
            const curItem = this.queue.shift();
            if (!curItem.defer) {
                curItem.callback();
                continue;
            }
            await defer(curItem.defer, curItem.callback)
        }
    }
}
比較
數(shù)組每一個(gè)都是構(gòu)造函數(shù)有點(diǎn)浪費(fèi)空間