async和await 优雅处理异步

function delay(word) {
    
    
    return new Promise((resolve, reject) => {
    
    
        setTimeout(()=>{
    
    
            resolve('hello ' + word)
        }, 2000)
    })
}

async function start(){
    
    
    const word1 = await delay('孙悟空')
    console.log(word1)
    const word2= await delay('猪八戒')
    console.log(word2)
    const word3 = await delay('沙悟净')
    console.log(word3)
}
start()

执行结果:

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没有嵌套地狱，也没有promise调用的多个括号和then，用变量就可接收异步的返回值，然后像同步代码一样书写，赞！！