> For the complete documentation index, see [llms.txt](https://chasethestar.gitbook.io/ko.learn-rxjs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://chasethestar.gitbook.io/ko.learn-rxjs/rxjs/subjects/replaysubject.md).

# ReplaySubject

## "Replays" or emits old values to new subscribers

[![Ultimate RxJS](https://drive.google.com/uc?export=view\&id=1qq2-q-eVe-F_-d0eSvTyqaGRjpfLDdJz)](https://ultimatecourses.com/courses/rxjs?ref=4)

### Examples

**Example 1: simple ReplaySubject**

( [Stackblitz](https://stackblitz.com/edit/rxjs-replaysubject-simple-example?file=index.ts\&devtoolsheight=100) )

```js
// RxJS v6+
import { ReplaySubject } from 'rxjs';

const sub = new ReplaySubject(3);

sub.next(1);
sub.next(2);
sub.subscribe(console.log); // OUTPUT => 1,2
sub.next(3); // OUTPUT => 3
sub.next(4); // OUTPUT => 4
sub.subscribe(console.log); // OUTPUT => 2,3,4 (log of last 3 values from new subscriber)
sub.next(5); // OUTPUT => 5,5 (log from both subscribers)
```

### Additional Resources

* [ReplaySubject](https://rxjs-dev.firebaseapp.com/api/index/class/ReplaySubject) 📰 - Official docs
* [ReplaySubject](https://indepth.dev/reference/rxjs/subjects/replay-subject) - In Depth Dev Reference

***

> 📁 Source Code: <https://github.com/ReactiveX/rxjs/blob/master/src/internal/ReplaySubject.ts>