What is a Promise?
Answer out loud or in your head first, then compare.
Answer
A Promise is an object that describes the result of work that may finish later. At first we wait for the result. Then the operation either succeeds with a value or fails with an error. You can get at the result with then and catch, or with await and try/catch.
For example, fetch() returns a Promise, because the network response isn't available straight away. A Promise itself isn't a separate thread or a mechanism that limits the number of requests. If I create a thousand fetch calls, I can start a thousand operations, even though they all return Promises.
Why it matters: It's a basic building block of asynchronous code in this role.
Possible follow-ups: Does a rejected Promise automatically stop the other requests?
How did it go? Be honest — “Not yet” puts the question on your review list.
Related questions
- Promise — Node.js
Practise in code
- At most three active operations — runs tests in your browser
Further reading
- Node.js: The Event Loop(opens in a new tab)Docs; accessed 22.10.2026. Event loop phases, timers and differences between Node/libuv versions.