callbag-from-obs

/**

• callbag-from-obs

• ---

• Convert an observable (or subscribable) to a callbag listenable source.
• npm install callbag-from-obs
• Example:
• Convert an RxJS Observable:

• const Rx = require('rxjs');
  

• const fromObs = require('callbag-from-obs');
  

• const observe = require('callbag-observe');
  

• const source = fromObs(Rx.Observable.interval(1000).take(4));
  

• observe(x => console.log(x)(source); // 0
  

•                                      // 1
  

•                                      // 2
  

•                                      // 3
  

• Convert anything that has the .subscribe method:

• const fromObs = require('callbag-from-obs');
  

• const observe = require('callbag-observe');
  

• const subscribable = {
  

•   subscribe: (observer) => {
  

•     let i = 0;
  

•     setInterval(() => observer.next(i++), 1000);
  

•   }
  

• };
  

• const source = fromObs(subscribable);
  

• observe(x => console.log(x))(source); // 0
  

•                                       // 1
  

•                                       // 2
  

•                                       // 3
  

•                                       // ...
  

*/

const $$observable = require('symbol-observable').default;

const fromObs = observable => (start, sink) => { if (start !== 0) return; let dispose; sink(0, t => { if (t === 2 && dispose) { if (dispose.unsubscribe) dispose.unsubscribe(); else dispose(); } }); observable = observable[$$observable] ? observable$$observable : observable; dispose = observable.subscribe({ next: x => sink(1, x), error: e => sink(2, e), complete: () => sink(2) }); };

module.exports = fromObs;