Exploring the reactive pattern to cache streams

You’ll be glad to know that RxJS ships with a very useful operator to implement a stream caching mechanism – this is the shareReplay multicast operator. Let’s take a look.

The shareReplay operator

In RxJS, shareReplay works similarly to the streaming service memory bank, sharing an Observable’s execution with multiple subscribers. When you subscribe to an Observable that uses shareReplay, it fetches the data, just like streaming a show. However, shareReplay caches or remembers the emitted values from the Observable. If you subscribe again later, instead of fetching the data again, it replays the cached values from its memory bank.

This can be useful when you have multiple subscribers to an Observable, but you don’t want each subscriber to trigger a new data fetch. Instead, you want them to share the same set of data, like multiple viewers sharing the same TV show episodes. This can improve performance...