By Rahul — Google Frontend Engineer
What Problem Does It Solve?
Before async/await, we had callback hell and promise chains. async/await lets you write asynchronous code that LOOKS synchronous.
How It Works Under the Hood
An async function ALWAYS returns a Promise. The await keyword pauses execution of the async function until the Promise resolves. Under the hood, it uses microtasks — the code after await is scheduled as a microtask.
Common Mistakes
Sequential When You Want Parallel
Forgetting Error Handling
await in Loops
Top-Level Await
Production Best Practices
- Always wrap await in try/catch
- Use Promise.all for independent async operations
- Add timeouts to avoid hanging forever:
Promise.race([fetch(url), timeout(5000)]) - Use AbortController to cancel fetch requests when components unmount
Summary
async/await is syntactic sugar over Promises. It makes async code readable but introduces subtle bugs around parallelism and error handling. Always use Promise.all for independent operations and try/catch for error handling.