Q15: What is a Promise and what are its three states?
A Promise represents the eventual completion or failure of an asynchronous operation. Its states are: 1) pending (initial state), 2) fulfilled (operation succeeded), 3) rejected (operation failed). State transitions are immutable once settled.
Key Takeaways
- Promises encapsulate async outcomes in pending, fulfilled, or rejected states.
- Transitions are permanent; settled states cannot change.
Knowledge Check
What occurs if resolve() and reject() are both called inside the same Promise executor?