AsyncPatternsintermediate

Promise.then callbacks are asynchronous (microtask)

📖 Usage Example

let x = 0;
Promise.resolve().then(() => { x = 1; });
// x is still 0 here — .then runs as a microtask

.then callbacks are microtasks — they run after synchronous code completes.

Microtask Queue

.then() callbacks are executed asynchronously as microtasks. They run after synchronous code but before macrotasks.

Challenge: Verify that a .then callback does not run synchronously.

💡 Hints (3)

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