Await promise without continue execution

Question

I have a part of code to retrieve some hardware device connected to PC. I also use a 3rd party library to retrieve these devices. I have done it in this way:

console.log("before");
// some code here 
(async () => {
  await 3dpartlibrary.getDevices().then(function (myDevices) {  
    for (var i = 0; i < myDevices.length; i++) {
      console.log(myDevices[i]); // i need this information to continue execution
    }
  });
})();
// here i would have a list of devices and i choose one from the list
console.log("after");

But the execution continues and I have the console messages after a bit of time. Actually i have in console the messages: before, after, and then devices.

I have put async in this way because cannot put in top of the function.

Probably async wait promise to resolve but the underneath code is goind ahead, i i would to obtain my list befor to go console.log("after") point.

How can I wait to have a list of devices before to continue execution?

What is the code surrounding the call to the anonymous async function? — Ben Aston, Mar 12 '20 at 14:43
*"How i can stop execution before that code is executed?"* Put all the remaining code after the `await ...` statement. As it is now the `async/await` part is useless. Your code behaves exactly as if you had just written `3dpartlibrary.getDevices().then(function (myDevices) { ... })`. What you want is probably: `(async () => { const myDevices = await 3dpartlibrary.getDevices(); for (...) { ... }; /* all the other code */ })();` — Felix Kling, Mar 12 '20 at 14:44
You can't stop execution. This feels like an [XY-problem](http://xyproblem.info/). What are you trying to achieve? — 3limin4t0r, Mar 12 '20 at 14:53
@3limin4t0r i have to wait for have a list of devices to use underneath — Max, Mar 12 '20 at 15:03
@52d6c6af its sequencial code, int that point i would have a list of devices from client system, before to continue — Max, Mar 12 '20 at 15:04
I recommend giving [How do I return the response from an asynchronous call?](https://stackoverflow.com/questions/14220321/how-do-i-return-the-response-from-an-asynchronous-call) a read. — 3limin4t0r, Mar 12 '20 at 15:53

score 0 · Answer 1 · answered Mar 12 '20 at 14:46

0

(async () => {
  let myDevices = await 3dpartlibrary.getDevices() 
  myDevices.forEach(console.log)
})();

answered Mar 12 '20 at 14:46

radulle

1,437
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19

While that's better I don't think it solves the OP's problem. – Felix Kling Mar 12 '20 at 14:47
This will wait for `3dpartlibrary.getDevices()`, isn't that what he wanted? – radulle Mar 12 '20 at 14:47
1

Note that this will `console.log` the index and array parameters passed to the callback of `forEach()` as well. – Patrick Roberts Mar 12 '20 at 14:48
It will, but that's what their code is doing already (in a less elegant way). I assume there is other code after that async function that is supposed to "wait". – Felix Kling Mar 12 '20 at 14:49
@Patrick True, but I'm guessing he was using console.log just for testing and that he would have a function that he would call. – radulle Mar 12 '20 at 14:50
@FelixKling you think that he maybe wants to wait for user input? – radulle Mar 12 '20 at 14:51

Await promise without continue execution

1 Answers1