Transducers with Ramda and RxJS

transducer.js

var Rx = require('rx');
var R = require('ramda');

var seq = Rx.Observable.range(1, 10);

var isEven = function isEven(x) { return x % 2 === 0; };
var add1 = function add1(x) { return x + 1; };

var transducer = R.compose(R.map(add1), R.filter(isEven));
var source = seq.transduce(transducer);

source.subscribe(
  function onNext(i) {
    document.body.textContent += ' ' + i;
  },
  function onErr(err) {
    document.body.textContent += ' ' + err;
  },
  function onComplete() {
    document.body.textContent += ' Done';
  }
);