JavaScript Tutorial: Async/Await
Write asynchronous code that reads like synchronous — async/await on top of Promises, error handling, parallel vs sequential, and real patterns.
The best thing that happened to JavaScript
`async/await` was introduced in 2017 and immediately changed how JavaScript is written. Instead of `.then().then().then()` chains, you write code that looks synchronous but runs asynchronously.
Under the hood, `async/await` is still Promises — just with much better syntax. Everything in Chapter 17 still applies.
What you'll learn in this JavaScript async/await tutorial
This interactive JavaScript tutorial has 8 hands-on exercises. Estimated time: 22 minutes.
- async/await basics — `async` makes a function return a Promise.
- await is just waiting — `await` pauses the async function — the rest of the program keeps running.
- Error handling with try/catch — With async/await, you use regular `try/catch` for errors — much cleaner than `.catch()` chains.
- Sequential vs parallel — critical difference! — This is the most important async/await performance trap.
- Async functions always return Promises — An `async` function ALWAYS returns a Promise — even if you return a plain value.
- Async iteration — for await...of — `for await...of` loops over async iterables — like paginated API responses or file streams.
- Async error propagation — Errors in async functions propagate naturally through the await chain.
- Build an async data fetcher with retry — Final challenge — no starter code.
JavaScript Async/Await concepts covered
- The best thing that happened to JavaScript