callbag-share/readme.md

Callbag operator that broadcasts a single source to multiple sinks

# callbag-share

Callbag operator that broadcasts a single source to multiple sinks. Does reference counting on sinks and starts the source when the first sink gets connected, similar to RxJS [`.share()`](https://www.learnrxjs.io/operators/multicasting/share.html). Works on either pullable or listenable sources.

`npm install callbag-share`

## example

Share a listenable source to two listeners:

```js
const interval = require('callbag-interval');
const observe = require('callbag-observe');
const share = require('callbag-share');

const source = share(interval(1000));

observe(x => console.log(x))(source); // 0
                                      // 1
                                      // 2
                                      // 3
                                      // ...

setTimeout(() => {
  observe(x => console.log(x))(source); // 3
                                        // 4
                                        // 5
                                        // ...
}, 3500);
```

Share a pullable source to two pullers:

```js
const fromIter = require('callbag-from-iter');
const share = require('callbag-share');

const source = share(fromIter([10,20,30,40,50]));

let talkback;
source(0, (type, data) => {
  if (type === 0) talkback = data;
  else console.log('a' + data);
});

source(0, (type, data) => {
  if (type === 1) console.log('b' + data);
});

talkback(1); // a10
             // b10
talkback(1); // a20
             // b20
```