Vazentra
Step through the event loop, call stack, and queues—see what the engine does before you guess what your code does.
console.log("A"); setTimeout(() => console.log("B"), 0); Promise.resolve().then(() => console.log("C"));
Call stack
main()
Web APIs
—
Task queue
(empty)
Console
A
Step through what the engine does with your code.
Pause and say what runs next—before you see it.
Confirm with the console and a short quiz.
Event loop · Call stack · Tasks & microtasks · Web APIs