observable array example by @andrestaltz in "You will learn RxJS at ng-europe 2016"

rx-array-observable.js

// 1 Nov 2016
// see https://www.youtube.com/watch?v=uQ1zhJHclvs
// by @andrestaltz

function map(transformFn) {
  var inputObservable = this;
  var outputObservable = createObservable(function subscribe(outputObserver) {    
    inputObservable.subscribe({
      next: function(x) {
        var y = transformFn(x)
        outputObserver.next(y)
      },
      error: function(e) {
        outputObserver.error(e)
      },
      complete: function () {
        outputObserver.complete()
      }
    })
  })
  return outputObservable
}

function filter(conditionFn) {
  var inputObservable = this;
  var outputObservable = createObservable(function subscribe(outputObserver) {    
    inputObservable.subscribe({
      next: function(x) {
        if (conditionFn(x)) {
          outputObserver.next(x)
        }
      },
      error: function(e) {
        outputObserver.error(e)
      },
      complete: function () {
        outputObserver.complete()
      }
    })
  })
  return outputObservable
}

function createObservable(subscribe) {
  return {
    subscribe: subscribe,
    map: map,
    filter: filter
  }
}

var clickObservable = createObservable(function subscribe(ob) {
  document.addEventListener('click', ob.next)
})

var arrayObservable = createObservable(function subscribe(ob) {
  ['10', 20, 30].map(ob.next)
  ob.complete()
})

var observer = {
  next: function (data) {
    console.log(data)
  },
  error: function (err) {
    console.error(err)
  },
  complete: function () {
    console.log('done')
  }
}

arrayObservable
  .map(function (x) {
    return x/10
  })
  .filter(function (x) {
    return x !== 2
  })
  .subscribe(observer)