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Discussion on: Asynchronous Javascript: 3 ways

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Replies for: In the last example, after the await keyword: does the program continue executing until the variable val is required (and waited upon) or does it "...

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Tom Butterwith •

Hi. Yes it's a blocking call. If you want to start the asynchronous function, do some other work, then wait for the return instead you can go with something like this:

const getPromise = () => Promise.resolve('My return value');
// the function is marked with the async keyword
const myFunction = async () => {  
  // tell the interpreter we want to wait on the response
  try {
    // start the asynchronous function
    const myPromise = getPromise();

    // Do some other work
    console.log("The function hasn't finished yet...");

    // Block execution till the promise has resolved
    const val = await myPromise;

    console.log(val); // prints 'My return value'
  } catch (error) {
    console.error(error.message);
  }
}