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How to Handle Asynchronous Callbacks Using Await?

Mary-Kate Olsen
Mary-Kate OlsenOriginal
2024-10-30 05:46:27921browse

How to Handle Asynchronous Callbacks Using Await?

Asynchronous Callback Handling with Await

In certain scenarios, while using callbacks like:

test() {
  api.on( 'someEvent', function( response ) {
    return response;
  });
}

you may need to incorporate asynchronicity. To make this function asynchronous and use await, you must first ensure that the callback function (someEvent) returns a Promise. This is because async functions rely on Promises to complete asynchronous operations.

A revised version of api.on():

function apiOn(event) {
  return new Promise(resolve => {
    api.on(event, response => resolve(response));
  });
}

Using this updated function, you can now modify test() to be an asynchronous function:

async function test() {
  return await apiOn( 'someEvent' );
}

However, asynchronous functions also return Promises, so the actual result value of test() is a Promise that can be resolved within another asynchronous function:

async function whatever() {
  // snip
  const response = await test();
  // use response here
  // snip
}

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