手写一个简易的用 Promise 加载一张图片

function loadImg(src){
    return new Promise((resove,reject)=>{
        const img = document.createElement('img')
        img.onload = ()=>{
            resove(img)
        }
        img.onerror = ()=>{
            let err = new Error('图片加载失败')
            reject(err)
        }
        img.src = src
    })
}

const url = 'https://qiniu.img.newtechcollege.com/c70fc3da'
const url2 = 'http://qiniu.newtechcollege.com/6dd24cb4'

loadImg(url).then(img => {
    console.log(img.width)
    return img
}).then(img=>{
    console.log(img.height)
    return loadImg(url2)
}).then(img => {
    console.log(img.src)
    return img
}).then(img=>{
    console.log(img.height)
})