Recommended Pattern to Cache Streams

The share operator

A lot of work was done in version 7 to consolidate multicasting operators. The multicast, publish, publishReplay, publishLast, and refCount operators were deprecated and will be removed in RxJS 8.

The only operators remaining are shareReplay, share, and connectable. The share operator rules them all, meaning that it’s highly recommended to use the share operator instead of Connectable and shareReplay in most cases. The shareReplay operator is too popular to deprecate but might be deprecated in future versions since there’s an alternative to it, especially because shareReplay, when not used carefully, can cause memory leaks, particularly with infinite streams.

The share operator is enhanced in version 7 with an optional configuration object as an argument, which makes it more flexible and ready to do the job of other operators. In this share configuration object, you can choose the subject you’re connecting through and define your reset behavior. This is how we can achieve the behavior of the shareReplay operator using the share operator: