share

signature: share(): Observable

Share source among multiple subscribers.

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💡 share is like multicast with a Subject and refCount!

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Examples

Example 1: Multiple subscribers sharing source

( StackBlitz | jsBin | jsFiddle )

// RxJS v6+ import { timer } from 'rxjs'; import { tap, mapTo, share } from 'rxjs/operators';  //emit value in 1s const source = timer(1000); //log side effect, emit result const example = source.pipe(  tap(() => console.log('***SIDE EFFECT***')),  mapTo('***RESULT***') );  /*  ***NOT SHARED, SIDE EFFECT WILL BE EXECUTED TWICE***  output:  "***SIDE EFFECT***"  "***RESULT***"  "***SIDE EFFECT***"  "***RESULT***" */ const subscribe = example.subscribe(val => console.log(val)); const subscribeTwo = example.subscribe(val => console.log(val));  //share observable among subscribers const sharedExample = example.pipe(share()); /*  ***SHARED, SIDE EFFECT EXECUTED ONCE***  output:  "***SIDE EFFECT***"  "***RESULT***"  "***RESULT***" */ const subscribeThree = sharedExample.subscribe(val => console.log(val)); const subscribeFour = sharedExample.subscribe(val => console.log(val));

Related Recipes

• Progress Bar

• Game Loop

• Save Indicator

Additional Resources

• share 📰 - Official docs

• Sharing streams with share 🎥 💵 - John Linquist

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📁 Source Code: https://github.com/ReactiveX/rxjs/blob/master/packages/rxjs/src/internal/operators/share.ts