Incorrect documentation about operator share.

[mocheng]

RxJS version:
5.4.3

Expected behavior:
The documentation of share should be correct.

Actual behavior:
The doc https://github.com/reactivex/rxjs/blob/master/src/operators/share.ts#L16 reads

This is an alias for .publish().refCount()

This is not correct. The operator share is actually a alias for .multicast(() => new Subject()).refCount(). There is difference between these two definition.

For .publish().refCount(), subscription after source completion will not re-execute the pipeline. However, for share(), subscription after source completion do re-execute the pipeline.

Check below example

import {Observable} from 'rxjs/Observable';
import 'rxjs/add/observable/interval';
import 'rxjs/add/operator/publish';
import 'rxjs/add/operator/take';

const tick$ = Observable.interval(1000).take(3);
const sharedTick$ = tick$.publish().refCount();

sharedTick$.subscribe(value => console.log('observer 1: ' + value));
setTimeout(() => {
  sharedTick$.subscribe(value => console.log('observer 2: ' + value));
}, 4500);

Output of above code is:

observer 1: 0
observer 1: 1
observer 1: 2

And for share:

import {Observable} from 'rxjs/Observable';
import 'rxjs/add/observable/interval';
import 'rxjs/add/operator/share';
import 'rxjs/add/operator/take';

const tick$ = Observable.interval(1000).take(3);
const sharedTick$ = tick$.share();

sharedTick$.subscribe(value => console.log('observer 1: ' + value));
setTimeout(() => {
  sharedTick$.subscribe(value => console.log('observer 2: ' + value));
}, 4500);

Above code has below output:

observer 1: 0
observer 1: 1
observer 1: 2
observer 2: 0
observer 2: 1
observer 2: 2

[benlesh]

Yup... you're right. That is a miss on the docs.

cc/ @ladyleet

[crunchie84]

I wanted to fix this but it seems that this is already (partly) addressed in https://github.com/ReactiveX/rxjs/blob/master/src/operator/share.ts but that is a different file (src/operator/xx vs src/operators/xx). Based on other files in those folders it is hard to discern where the documentation should reside.

@benlesh @ladyleet which of those paths should be the one containing the documentation of the operator?

[staltz]

Done with PR #2990

[lock]

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