Node.js Async/Await

Node.js Async/Await

Async/Await is a modern way to write asynchronous code in Node.js.
It is built on top of Promises but looks and behaves like synchronous code — making it easier to read, write, and debug.

1. What is async?

A function becomes asynchronous when you add the async keyword.

Example:

An async function always returns a Promise.

2. What is await?

await is used inside an async function and makes JavaScript wait until a Promise is resolved or rejected.

Example:

Why Use Async/Await?

✔ Cleaner and more readable than Promises
✔ No callback hell
✔ Easy error handling using try...catch
✔ Looks like synchronous code

Async/Await Example with File Reading

Using fs.promises:

Async/Await With Custom Promise

Error Handling with Async/Await

Use try...catch for clean error handling:

Multiple Awaits (Sequential Execution)

Running Promises in Parallel

Instead of:

Use:

This runs both tasks at the same time = faster.

Rules for Async/Await

1. await works only inside an async function

2. Async functions always return a Promise

3. Use try...catch to handle errors

4. Cleanest method for asynchronous code

Async/Await vs Promises vs Callbacks