JavaScript · Module 9 of 10

Asynchronous JavaScript

Handle slow work like network calls with callbacks, promises and async/await.

📖 Key ideas

JavaScript runs one thing at a time but does not wait for slow tasks; it continues and comes back later.
setTimeout(fn, 1000) runs fn after a delay.
A Promise represents a value that arrives later: then() and catch().
async/await makes promise code read top to bottom.
Use try/catch with await to handle errors.

💡 Real-life example: Ordering food at a restaurant: you get a token (promise), sit down, and your food arrives later without you standing at the counter.

PromiseA value that will arrive later

awaitWaits for a promise inside async functions

setTimeoutRuns code after a delay

catchHandles a rejected promise