Transducer support coming in 2.3.14

transducer.js

  /**
   * Executes a transducer to transform the observable sequence 
   * @param {Transducer} transducer A transducer to execute
   * @returns {Observable} An Observable sequence containing the results from the transducer.
   */
  observableProto.transduce = function(transducer) {
    var source = this;

    function transformForObserver(observer) {
      return {
        init: function() {
          return observer;
        },
        step: function(obs, input) {
          return obs.onNext(input);
        },
        result: function(obs) {
          return obs.onCompleted();
        }
      };
    }

    return new AnonymousObservable(function(observer) {
      var xform = transducer(transformForObserver(observer));
      return source.subscribe(
        function(v) { xform.step(observer, v);}, 
        observer.onError.bind(observer), 
        function() { xform.result(observer); }
      );
    });
  };

usage.js

var Rx = require('rx');
var t1 = require('transducers-js');
var t2 = require('transducers.js');

function even (x) { return x % 2 === 0; }
function mul10(x) { return x * 10; }

// Using cognitect's transducers
Rx.Observable.range(1, 5)
  .transduce(t1.comp(t1.filter(even), t1.map(mul10)))
  .subscribeOnNext(function (x) {
    console.log('Cognitect Next: %d', x);
  });

// => Cognitect Next: 20
// => Cognitect Next: 40

// Using jlongster's transducers
Rx.Observable.range(1, 5)
  .transduce(t2.compose(t2.filter(even), t2.map(mul10)))
  .subscribeOnNext(function (x) {
    console.log('jLongster Next: %d', x);
  });
  

// => jLongster Next: 20
// => jLongster Next: 40