how to use the connectable function from the rxjs library in javascript

The connectable() function from RxJS library is used to transform a cold observable into a hot observable that can be shared and replayed among multiple subscribers. It returns a special ConnectableObservable that can be connected and disconnected at will.

To use connectable(), you need to first create an observable and then use the pipe() method to chain the connectable() operator to the observable. This returns a ConnectableObservable. You can then call the connect() method on the ConnectableObservable to activate it and start emitting values.

Here's an example:

index.tsx
import { interval } from 'rxjs';
import { take, tap } from 'rxjs/operators';
import { connectable } from 'rxjs/operators';

const source = interval(1000).pipe(
  take(5),
  tap(() => console.log('tap'))
);

const connectableSource = source.pipe(connectable());

connectableSource.subscribe(x => console.log(`Subscriber 1: ${x}`));
connectableSource.subscribe(x => console.log(`Subscriber 2: ${x}`));

connectableSource.connect();
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In this example, we create an interval observable that emits a value every second and stops after 5 emissions. We use the take() operator to limit the observable to 5 emissions, and the tap() operator to log a message at each emission.

We then use the connectable() operator to transform the cold observable into a hot observable. We subscribe to the ConnectableObservable twice, each with a different subscriber. Finally, we call the connect() method on the ConnectableObservable to start emitting values.

Now, when the ConnectableObservable is connected, both subscribers will receive the same values emitted by the original observable, but with the difference that the tap() operator will execute only once at each emission because the source observable has become hot.