Glossary term
What is promise? Meaning for developers
In JavaScript Core
An object standing in for a value that will arrive later. Its .then callbacks go to the microtask queue.
Learn it properly · JavaScript CoreLesson 14: Async JS and the Event LoopCall stack, Web APIs, callback queue, microtask queue and the event loop that ties them together, stepped tick by tick — plus async/await, where rendering fits, starvation, and why setTimeout(0) is not 0.In JavaScript Part 2
An object for a value that arrives later. It is pending, then fulfilled or rejected.
Learn it properly · JavaScript Part 2Lesson 2: Promises and async/await From the Ground UpPromise states, microtask order, a promise built by hand, async/await, the combinators and AbortController.