RxJS
RxJS (Reactive Extensions for JavaScript) is a library for reactive programming using Observables, to make it easier to compose asynchronous or callback-based code. It provides a powerful way to handle events, asynchronous operations, and data streams in a declarative manner, often used in web applications for state management and UI updates. The library implements the Observable pattern, allowing developers to work with sequences of data over time.
Developers should learn RxJS when building applications that involve complex asynchronous workflows, such as real-time data streams, event handling, or state management in frameworks like Angular. It is particularly useful for handling user interactions, API calls, and WebSocket connections in a scalable and maintainable way, reducing callback hell and improving code readability. Use cases include debouncing user input, combining multiple API responses, and managing application state with reactive patterns.