How to add a timeout in a promise?

Question

I have read many different ways of adding timeouts within a promise, but most, if not all, seem to utilise the setTimeout() method. By definition:

The setTimeout() method calls a function or evaluates an expression after a specified number of milliseconds.

What I am looking for is a way to say:

"If the function executed inside the promise (that will either resolve or
reject the promise), does not complete within a specified x number of
milliseconds, automatically reject or raise an exception."

If this is the same as the defined above (using the setTimeout() method), an explanation would be highly appreciated!

Answer 1

You can wrap setTimeout in a Promise and create a little "wait"-function which you can then use with Promise.race:

function wait(ms) {
   return new Promise((_, reject) => {
      setTimeout(() => reject(new Error('timeout succeeded')), ms);
   });
}

try {
  const result = await Promise.race([wait(1000), yourAsyncFunction()]);
} catch(err) {
  console.log(err);
} 

With this code Promise.race will reject if yourAsyncFunction takes longer than 1000 ms to resolve/reject, otherwise result will yield the resolved value from yourAsyncFunction.