Using an await in function parameter

Question

Is it possible to use await with a parameter? for example:

const run = async () => {
  getStudentDetails(await getStudentId());
}

Even if it is, it seems like it might not be the best idea. Anyone done this before?

Answer 1

Yes, you can use await expressions in every arbitrary context (where it parses) inside the async function, including as arguments to function calls. There's nothing wrong with it.

It's equivalent to

const run = async () => {
  const studentId = await getStudentId();
  getStudentDetails(studentId);
}

Answer 2

I do it all the time. However in case if you want to pass more than one parameter to function they will be resolved sequentially. To fight that problem I wrote an util function which looks like that:

async function call(func, ...args) {
    return func(...await Promise.all(args));
}

(async function() {
        console.log(await call(functionToCall, delay(2000), delay(2000)));
})();

With that syntax functionToCall will be called in 2 seconds instead of 4

Answer 3

Yes, this will work, as you can use the await keyword everywhere where you can use an expression.

However, I'd prefer a slightly updated version of your code for better readability (and for better debugability, too):

const run = async () => {
  const studentId = await getStudentId();

  getStudentDetails(studentId);
}

I hope this helps 😊