实现下面这道题中的machine函数function machine() { }machine(‘ygy’).execute() // start ygymachine(‘ygy’).do(’eat’).execute(); // start ygy// ygy eatmachine(‘ygy’).wait(5).do(’eat’).execute();// start ygy// wait 5s（这里等待了5s）// ygy eatmachine(‘ygy’).waitFirst(5).do(’eat’).execute();// wait 5s// start ygy// ygy eat原型写法维护一个数组，异步就push函数，不是异步就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 ${times}s) return new Promise((resolve)=>{ setTimeout(()=>{resolve()},times*1000) }) }}machine.prototype.execute = async function(){ const logs = this.logs if(logs.length > 0){ for(let i=0; i<logs.length; i++){ if(typeof(logs[i]) === ‘function’){ await logsi }else { console.log(logs[i]) } } }};machine.prototype.do = function(argument){ this.logs.push(${this.name} ${argument}s) return this};machine.prototype.wait = function(item){ this.logs.push(machine.defer(item)) return this};machine.prototype.waitFirst = function(item){ this.logs.unshift(machine.defer(item)) return this};es6写法维护一个queue队列数组，里面全部是构造函数，第一个参数代码是否异步，第二个是callbackfunction 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) } }}比较数组每一个都是构造函数有点浪费空间