What are the common use cases of observables?

An Observable (popularized by RxJS and reactive programming) represents a lazy, push-based stream of multiple values emitted over time. Observables excel at handling asynchronous event streams that emit repeatedly:

### 1. Real-Time Data Feeds & WebSockets
Push-based data streams where the server sends continuous updates (stock tickers, live chat messages, crypto prices, sports scores):

const socketStream$ = webSocket('wss://stream.example.com').pipe(
  filter(msg => msg.type === 'PRICE_UPDATE'),
  map(msg => msg.payload)
);

### 2. User Input Handling & Auto-Complete Search
Handling rapid keyboard input with debouncing, distinct value checks, and automatic request cancellation:

searchInput$.pipe(
  debounceTime(300),
  distinctUntilChanged(),
  switchMap(query => api.search(query)) // Cancels previous pending request if new query arrives
);

### 3. Complex Asynchronous Orchestration
Cases requiring retry logic with exponential backoff (retryWhen), timeouts (timeout), parallel coordination (forkJoin, combineLatest), or race conditions (race).

### 4. Periodic Polling & Heartbeats
Scheduling repeating background requests using interval(5000) combined with takeUntil for clean unsubscription when components unmount.