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//new Promise(resolve,reject,finally); //只有两种结果，回调的升级版，一段时间才执行，因此可以进行异步的处理，防止阻塞。
const isPregnant = false;
const promise = new Promise((resolve, reject) => {
    if (isPregnant) {
        resolve('孩子的父亲')
    } else {
        reject('女孩的老公')
    }
})
promise.then(name => {
    console.log(`男人成为了${name}`)
}).catch(name => {
    console.log(`男人成为了${name}`)
}).finally(() => {
    console.log(`男人和女孩最终结婚了`)
})

//
const imgAddress = 'https://timsa.baidu.com'
const imgPromise = (url) => {
    return new Promise((resolve, reject) => {
        const img = new Image();
        img.src = url;
        img.onload = () => {
            resolve(img);
        }
        img.onerror = () => {
            reject(new Error('图片有误'));
        };
    });
};
imgPromise(imgAddress)
    .then(img => {
        document.body.appendchild(img);
    })
    .catch(err => {
        document.body.innerHTML = err;
    });