operators/do.js

  1. import { Observable } from '../Observable';
  2. import { passThroughNext } from './passThroughNext';
  4. /**
  5.  * Will run some callback before passing the current value to the subscription
  6.  * 
  7.  * @memberof operators
  8.  *
  9.  * @param {Observable} source$
  10.  * @param {Function} runCallback
  11.  * @returns {Observable}
  12.  *
  13.  * @example
  14.  * doStuff(obs$, (value) => console.log(value))
  15.  *  .subscribe((sameValue) => console.log('Will log the same value: ', sameValue))l
  16.  */
  17. export const doStuff = function (source$, runCallback) {
  18.   return passThroughNext(source$, function ({ next }, value) {
  19.     runCallback(value);
  20.     
  21.     next(value);
  22.   });
  23. };
  25. Observable.do = doStuff;
  26. Observable.prototype.do = function (runCallback) {
  27.   return doStuff(this, runCallback);
  28. };