Javascript异步/等待回调函数

Question

I'm wondering if async/await behave the same in the following two 'super-basic' examples:我想知道 async/await 在以下两个“超级基本”示例中的行为是否相同：

async function blah1() {
  return await foo.bar().then('Done');
}

as this作为这个

async function blah2() {
  return blah3(foo.bar());
}

async function blah3(fn) {
  return await fn.then('Done');
}

or is there some important difference?还是有一些重要的区别？

Yes I know 'return await' is redundant but I left it in for this example :)是的，我知道 'return await' 是多余的，但我把它留在了这个例子中 :)

Answer 1

async function blah1() {
  return await foo.bar().then('Done');
}

blah1()

Calls foo.bar , which returns a promise, to which a then is added.调用foo.bar ，它返回一个承诺， then添加一个承诺。

The resultant promise is returned.结果承诺被返回。

async function blah2() {
  return blah3(foo.bar());
}

async function blah3(fn) {
  return await fn.then('Done');
}

blah2()

Calls foo.bar , which returns a promise, which is passed to blah3 , which adds a then .调用foo.bar ，它返回一个承诺，它被传递给blah3 ，它添加了一个then 。

The resultant promise is returned from blah3 to blah2 and thence to the caller.结果承诺从blah3返回到blah2 ，然后返回给调用者。

I'd say no meaningful behavioral difference.我会说没有有意义的行为差异。