how to use the subscription function from the rxjs library in typescript

To use the subscription function from the rxjs library in TypeScript, you first need to install rxjs via npm. Open your terminal and run the following command:

index.ts
npm install rxjs
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Afterwards, you can import the subscription and observable classes to your TypeScript file:

index.ts
import { Observable, Subscription } from 'rxjs';
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Once you have imported the necessary classes, you can create an observable and subscribe to it using the subscription function:

index.ts
const observable = new Observable<number>(subscriber => {
  let count = 0;

  const intervalId = setInterval(() => {
    subscriber.next(count++);
  }, 1000);

  return () => {
    clearInterval(intervalId);
  };
});

const subscription = observable.subscribe((value) => {
  console.log(`Received value: ${value}`);
});
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In the above example, we are creating a basic observable that emits a new value every second. We then subscribe to this observable using the subscription function and log out each new value that is emitted.

To stop the observable from emitting values and clean up any resources associated with it, you can call the unsubscribe function on the subscription object:

index.ts
subscription.unsubscribe();
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This will stop the observable from emitting any new values and clean up any resources associated with it.