Skip to content

Async Functions

Async Functions

Introduction

An async function is a function that always returns a Promise. It allows you to use the await keyword inside it.

Basic Syntax

// An async function always returns a Promise
async function getData() {
  return 'Hello';
}

console.log(getData()); // Promise { 'Hello' }
getData().then(console.log); // 'Hello'

Arrow Functions

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

// With params
const fetchUser = async (id) => {
  const response = await fetch(`/api/users/${id}`);
  return response.json();
};

Visual Explanation

flowchart TD
    A["async function fetchData()"]
    B["await fetch('/api/data')"]
    C["⏳ Pauses here until Promise resolves"]
    D["Continues with result"]
    E["Returns a Promise automatically"]

    A --> B
    B --> C
    C --> D
    D --> E

Summary

async keyword makes a function return a Promise
Works with function declarations, expressions, and arrow functions
Inside an async function, you can use await
The returned value is automatically wrapped in a resolved Promise

Further Reading

MDN: async function