What is Subscription?

AngularJunior~1 min read

Subscription in RxJS is an object that appears when you subscribe to an Observable. It manages the connection between the stream and your code.

Example:

import { interval } from 'rxjs';

const stream$ = interval(1000);

const subscription = stream$.subscribe(value => {
  console.log('Tick:', value);
});

Here:

subscription is the Subscription itself
it "connects" you to the stream

Why it's needed:

To unsubscribe, meaning stop the stream and free up resources.

subscription.unsubscribe();

If you don't do this, the stream can run forever (for example, interval()), and cause a memory leak or unnecessary load.

Where it's used:

In Angular components (ngOnDestroy)
When working with infinite streams
To manually control when the stream should stop

Conclusion:

Subscription is like a remote control for an Observable. You subscribe, you get data. You unsubscribe, the stream stops.

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What is Subscription?

#Example:

#Why it's needed:

#Where it's used:

#Conclusion:

Short Answer

Example:

Why it's needed:

Where it's used:

Conclusion: