SOURCE

function promiseClick() {
    let p = new Promise(function (resolve, reject) {
        setTimeout(function () {
            var num = Math.ceil(Math.random() * 20); //生成1-10的随机数
            console.log('随机数生成的值：', num)
            if (num <= 10) {
                resolve(num);
            }
            else {
                reject('数字太于10了即将执行失败回调');
            }
        }, 2000);
    })
    return p
}

promiseClick().then(
    function (data) {
        console.log('resolved成功回调');
        console.log('成功回调接受的值：', data);
    },
    function (reason) {
        console.log('rejected失败回调');
        console.log('失败执行回调抛出失败原因：', reason);
    }
);