JavaScriptMed
JavaScript Async/Await — From Basics to Advanced Patterns
Async/await is syntactic sugar over Promises that makes asynchronous code look and behave more like synchronous code. The async keyword makes a function return a Promise, and the await keyword pauses execution until a Promise settles. This leads to cleaner, more readable code compared to Promise chains.
6 concepts·6 practice problems·Intermediate level
Key Concepts
- •async function always returns a Promise
- •await pauses execution until Promise settles
- •await can only be used inside async functions
- •Top-level await available in ES2022 (modules)
- •async/await is just Promise syntax sugar
- •Sequential by default, parallel with Promise.all()
Topics Covered
Async/Await Syntax BasicsSyntactic sugar for PromisesError Handling with Async/Awaittry/catch with async/awaitParallel Async OperationsRunning async operations in parallel with Promise.allPromises Deep DiveAsync operations and combinatorsPromise ChainingSequential async operations in a flat structureEvent LoopHow async JavaScript works
Practice Problems
Common Mistakes to Avoid
- ×Using await in non-async functions
- ×Forgetting that async functions return Promises
- ×Creating accidental sequential execution when parallel is needed
- ×Not handling errors with try/catch
Interview Tips
- ✓Know that async/await is Promise syntax sugar
- ✓Understand sequential vs parallel execution
- ✓Know top-level await is ES2022+
- ✓Be able to convert between Promise chains and async/await