异步函数返回一个承诺

Question

I found an example on the web that looks like the following:

async function asyncFunc() {
    return Promise.resolve(123);
}
asyncFunc()
  .then(x => console.log(x)) // 123

However, I can also write it like that:

async function asyncFunc() {
    return 123
}
asyncFunc()
  .then(x => console.log(x)) // 123

I mean, I can find a use case for returning a resolved answer (for example, memoization/caching), But why should I actually use it if I can simply return the result, straightforward?

Answer 1

From https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/async_function :

When an async function is called, it returns a Promise. When the async function returns a value, the Promise will be resolved with the returned value. When the async function throws an exception or some value, the Promise will be rejected with the thrown value.

Emphasis mine.

Both your examples are totally valid, although returning a resolved promise in the first case is unnecessary. Any async function that returns a plain value will wrap that value into a resolved promise automatically. I think typically people prefer the second example, as it's more straightforward.