Promises

Summary

An object representing the eventual result (or failure) of an asynchronous operation — the modern foundation for handling async code cleanly instead of nested callbacks. Promise composition makes asynchronous workflows easier to coordinate, including parallel operations, sequential dependencies, cancellation patterns, and error propagation.

• 1Wrap a `setTimeout` in a Promise and consume it with `.then()`/`.catch()`. Validate your understanding by applying it in a small practical example.
• 2Practice `Promise.all()` to run multiple async operations in parallel. Test it with at least one normal case and one edge case so you can explain the behavior confidently.
• 3Learn the three states of a Promise: pending, fulfilled, rejected.