In order to use await, the function directly enclosing it needs to be async. According to your comment, adding async to the inner function fixes your issue, so I’ll post that here: Possibly, you could remove the async from the outer function because it does not contain any asynchronous operations, but that would depend on … Read more
I am not very sure whether it will make any difference in performance of my API. Bear in mind that the primary benefit of asynchronous code on the server side is scalability. It won’t magically make your requests run faster. I cover several “should I use async” considerations in my article on async ASP.NET. I think your use case (calling … Read more
Your sleep function does not work because setTimeout does not (yet?) return a promise that could be awaited. You will need to promisify it manually: Btw, to slow down your loop you probably don’t want to use a sleep function that takes a callback and defers it like this. I recommend: which lets the computation of parents take at least 5 seconds.
Sure the code does work, but I’m pretty sure it doesn’t do what you expect it to do. It just fires off multiple asynchronous calls, but the printFiles function does immediately return after that. Reading in sequence If you want to read the files in sequence, you cannot use forEach indeed. Just use a modern for … of loop instead, in which await will … Read more
I’m wondering if there is any way to get a value from a Promise or wait (block/sleep) until it has resolved, similar to .NET’s IAsyncResult.WaitHandle.WaitOne(). I know JavaScript is single-threaded, but I’m hoping that doesn’t mean that a function can’t yield. The current generation of Javascript in browsers does not have a wait() or sleep() that allows other things … Read more
Although similar in general cases (“run and get results for many tasks”), each function has some specific functionality for other cases: asyncio.gather() Returns a Future instance, allowing high level grouping of tasks: All tasks in a group can be cancelled by calling group2.cancel() or even all_groups.cancel(). See also .gather(…, return_exceptions=True), asyncio.wait() Supports waiting to be stopped after the first … Read more
Update Jan 2021: You can even do it in the Node REPL interactive using –experimental-repl-await flag A new answer to an old question. Today ( Jan 2017 June 2019) it is much easier. You can use the new async/await syntax. For example: For using async/await out of the box without installing and plugins, you have to use node-v7 or node-v8, using the –harmony flag. Update June … Read more
In the above, you have an async function (the arrow function) which uses await inside. This is fine (albeit pointless as you could return the promise directly). Here: You use await again, and while the function on the right-hand side does return a promise, the function it appears inside is not async so it is not valid. Put it inside an … Read more
I am using Discord.js and I have no idea how to get the value out of a Promise. Here is some context: and I get the output: My issue is that I can obviously get my username and print it to console, but I can’t get it out of the Promise. How do I get … Read more
Async arrow functions look like this: Async arrow functions look like this for a single argument passed to it: Async arrow functions look like this for multiple arguments passed to it: The anonymous form works as well: An async function declaration looks like this: Using async function in a callback: Using async method inside of a class: