2013年1月22日 · When you use await, it sets the rest of the method as a continuation to be executed when whatever you await-ed is complete. It exits the method that you used it in, so the caller can continue. Then when the await-ed line is actually complete, it finishes the remainder of that method on some thread (usually a worker thread). –

2016年6月2日 · After the await defers the continuation of the async function, execution of subsequent statements ensues. If this await is the last expression executed by its function execution continues by returning to the function's caller a pending Promise for completion of the await's function and resuming execution of that caller.

2020年12月15日 · This is an elegantly minimalistic answer, but I don’t understand why the get_page function needs to have the async prefix. When I implement this pattern without that prefix, it works the same. My understanding is that async permits await prefixes, but you don’t have any, and Promisifies non-Promise return values, but you don’t return any.

2012年9月17日 · The async modifier just tells the compiler to generate an async state machine to manage any await keywords it encounters within the method (more to manage the lines after the awaits). It doesn't do anything as far as externally viewing the method. i.e., it doesn't make the method usable by await. await only depends on the method returning a ...

2016年1月16日 · In contrast to await task created in such a way is differ from original inner task. See the Unwrap() docs, ...

2017年7月24日 · There is a difference between calling t1 = task1(); t2 = task2() and then using await afterwards for both of them result1 = await t1; result2 = await t2; like in his question, as opposed to what you're testing which is using await on the original call like result1 = await task1(); result2 = await task2();. The code in his question does start ...

What await does is it returns the result of the operation immediately and synchronously if the operation has already completed or, if it hasn't, it schedules a continuation to execute the remainder of the async method and then returns control to the caller. When the asynchronous operation completes, the scheduled completion will then execute.

async function test() { return await apiOn( 'someEvent' ); // await is actually optional here // you'd return a Promise either way. But that's a lie too, because async functions also return Promises themselves, so you aren't going to actually get the value out of test() , but rather, a Promise for a value, which you can use like so:

then isn't worse than await because it older. It's just different, and suited for other things. This "await to(…) style" on the other hand is reminiscent of the nodeback style with all its disadvantages. –

2018年2月25日 · async and await are syntactic sugar intended to make coding around Promise APIs simpler and cleaner. They have no performance impact; however a Promise-based API behaves, it behaves the same way when used via async and await. –