console.clear()
 console.log('x')
var edges =  [
	[ ], // 0
  [2], // 1
  [4,6], //2
  [4,5], //3
  [2,3,5], //4
  [3,4,6] //5
]

var source = Rx.Observable
  .of([1,5,3,6,4,2])
  .map(() => ({
    s: [3],
    r: [1,5,6,4,2].reverse()
  }))
  .expand(({s,r}) => {
    let step = []
    s.forEach(nodeWithMsg => {
      let index = r.findIndex(x => edges[nodeWithMsg].includes(x))

      if(index != null) {
        step = [...step, ...r.splice(index, 1)]
      }

    })

   return Rx.Observable.of({
     s: s.concat(step),
     r
   })
  })
  .do(console.log)
  .filter(({r}) => r.length === 0)
  .take(1)

var subscription = source.subscribe(
  function (x) {
    console.log('Next: %s', x);
  },
  function (err) {
    console.log('Error: %s', err);
  },
  function () {
    console.log('Completed');
  });