Generator函數(shù)實現(xiàn)

function* gen(x){var y = yield x + 2;return y }//1.調(diào)用g函數(shù)會返回一個內(nèi)部的指針 var g = gen(1);//2.每次調(diào)用next會返回一個對象,{value,done}表示當(dāng)前階段的信息 g.next()//{value:3,done:false} //3.如果第二次調(diào)用next方法,傳入了參數(shù)則會作為上一階段next的返回結(jié)果 g.next(2)//{value:2,done:true}

自動執(zhí)行g(shù)enerator函數(shù)

let i = 0 function getNumber(){return new Promise((resolve,reject) => {setTimeout(() => {resolve(++i)},1000)}) }function *read(){let a = yield getNumber();console.log(a)let b = yield 'b'console.log(b)let c = yield getNumber();console.log(c) }function co(gen){return new Promise((resolve, reject) => {let g = gen()function next(lastValue){let { value, done } = g.next(lastValue)if(done){resolve(lastValue)} else {if(value instanceof Promise){value.then(next,err => reject(err))} else {next(value)}}}next()}) } co(read).then((data) => {console.log(data) },(reason) => {console.log(reason) })

轉(zhuǎn)載于:https://www.cnblogs.com/pluslius/p/10572478.html

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