JavaScript: promises, async, and the event loop

What you’ll practice

From promise chains to async/await, this quiz focuses on how JavaScript schedules work across the call stack, task queue, and microtask queue.

Each question has 4 options and there’s no timer, so you can reason through tricky execution-order scenarios without rushing.

Difficulty and quiz setup

Difficulty is mixed on purpose: you’ll see quick concept checks alongside deeper “predict the output” items that test real understanding.

Choose your question count and difficulty before starting to tailor the session—short for warm-ups, longer for thorough review.

Common pitfalls to watch for

Many bugs come from assuming promises behave like setTimeout, or from forgetting that microtasks run before the next macrotask.

- Confusing microtasks (Promise callbacks) with macrotasks (timers, I/O) - Forgetting that async functions return a Promise immediately - Misreading then/catch/finally chaining and return values - Assuming await “blocks” the thread instead of yielding to the event loop - Missing error propagation rules and unhandled rejection behavior n## Tips for improving fast

Aim to explain the scheduling step-by-step (stack → microtasks → macrotasks) rather than guessing the final output.

Replaying missed questions with a smaller question count is a great way to lock in the patterns that keep showing up in real projects.