去想在a函数里得到then的值

Question

function a(){
    const promise1 = new Promise((resolve, reject) => {
        resolve('Success!');
    });

    var output ;

    promise1.then((value) => {
        output = value;
    });

    return  output;
}
console.log(a())  //underfind

我想得到then里面的value值 但是打不到 我那里错了呢？

Answer 1

Promise是异步的,看看这个： https://wenyuanblog.com/blogs/javascript-how-to-return-value-in-promise.html https://wenyuanblog.com/blogs/javascript-how-to-return-value-in-promise.html