关于promise对象处理异步

<script>
        // resolve,reject是两个回调函数，用于获取异步API setTimeout的返回值
        var promise = new Promise((resolve, reject) => {
            setTimeout(() => {
                if (true) {
                    resolve({
                        name: '张'
                    })
                } else {
                    reject('失败了')
                }
            }, 2000)

        });
        promise.then((a) => {
            // 此处的函数就是对resolve回调函数的声明
            console.log(a)
        })
    </script>