003--面试之promise

佚名 6年前 (2019-05-09) 随笔 1894人围观抢沙发百度已收录

传统的异步加载使用callback

SRE实战互联网时代守护先锋，助力企业售后服务体系运筹帷幄！一键直达领取阿里云限量特价优惠。

ES6 promise的加载

function loadImg(src) {
    var promise = new Promise(function (resolve, reject) {
        var img = document.createElement('img')
        img.onload = function () {
            resolve(img)
        }
        img.onerror = function () {
            reject('图片加载失败')
        }
        img.src = src
    })
    return promise
}

var src1 = 'https://www.imooc.com/static/img/index/logo_new.png'
var src2 = 'https://img1.mukewang.com/545862fe00017c2602200220-100-100.jpg'

const load = async function () {
    const result1 = await loadImg(src1)
    console.log(result1)
    const result2 = await loadImg(src2)
    console.log(result2)
}
load()