Async function syntax in Javascript - Cheat Sheet & Quick Revision

Recall & Review

beginner

What keyword is used to declare an async function in JavaScript?

The async keyword is used before the function keyword or before the parentheses in arrow functions to declare an async function.

beginner

What does an async function always return?

An async function always returns a Promise, even if you return a simple value inside it.

beginner

How do you wait for a Promise to resolve inside an async function?

Use the await keyword before the Promise to pause the function execution until the Promise resolves.

beginner

Show the syntax of an async arrow function that returns the string 'Hello'.

const greet = async () => {
  return 'Hello';
};

beginner

Why use async functions instead of regular functions when working with Promises?

Async functions let you write asynchronous code that looks like normal, synchronous code, making it easier to read and maintain.

Which keyword is used to declare an async function?

A async

B await

C promise

D defer

The async keyword declares an async function.

What does an async function return by default?

A A callback

B A Promise

C Undefined

D A number

Async functions always return a Promise.

How do you pause an async function until a Promise resolves?

A Using setTimeout

B Using async

C Using then

D Using await

The await keyword pauses the async function until the Promise resolves.

Which of these is a correct async function declaration?

A async function fetchData() {}

B function async fetchData() {}

C await function fetchData() {}

D function fetchData async() {}

The correct syntax is async function functionName() {}.

What is the benefit of using async functions?

A They replace all callbacks automatically

B They run code faster

C They make asynchronous code easier to read

D They prevent errors

Async functions make asynchronous code look like synchronous code, improving readability.

Explain how to declare an async function and how it behaves differently from a regular function.

Think about the keywords and what the function returns.

Describe how the await keyword works inside an async function.

Consider what happens when you use await before a Promise.