RxJX

CatchFlapMapAsync.js

'use strict';

var Rx = require('rx');
var Promise = require('bluebird');

function getPromiseByNum(num) {
  if (num < 2) {
    return Promise.resolve(num);
  } else {
    return Promise.reject(num);
  }
}

var source = Rx.Observable.interval(1000)
.flatMap(function(num) {
  return Rx.Observable.fromPromise(getPromiseByNum(num))
                                    .catch(function(e) { return Rx.Observable.just({error : e}); });
});

var subscription = source.subscribe(
  function (x) {
    if (x.error) console.log('Error: ' + x.error);
    else console.log('Next: ' + x);
  },
  function (err) {
    console.log('Error: ' + err);
  },
  function () {
    console.log('Completed');
  });

to.js

var Rx = require('rx');