ThreeHammers3_streams

-------click-------click---------click------->

**********************************************

----------------"a=1&a=2&b=3"---------------->

**********************************************

------------"a=1&a=2&b=3"-------------------->
          observablePerPair
           \      \     \
           "a=1"  "a=2"  "b=3"
             \      \      \
              \   flatmap   \
-------------"a=1"--"a=2"--"b=3"------------->

**********************************************

---------------"a=1"--"a=2"--"b=3"----------->
               .map(splitEqual)
---------["a", "1"]--["a", "2"]--["b", "3"]-->

**********************************************

-------------------{a: null}----------------->

-------------------{b: null}----------------->

**********************************************

------------["a", "1"]--["a", "2"]----------->
               .scan(scanArray)
------------------["1", "2"]----------------->

and

------------------["b", "3"]----------------->
               .scan(scanArray)
----------------------["3"]------------------>

**********************************************

------------------["1", "2"]----------------->
     .map(extractValueFromSingleArray)
------------------["1", "2"]----------------->

and

---------------------["3"]------------------->
     .map(extractValueFromSingleArray)
----------------------"3"-------------------->

**********************************************

//Rx.Observable.just(objectFromKey(obs.key))
-------------------{a:null}------------------> 
//obs
-------------------["1","2"]-----------------> 

**********************************************

--------------{a: null}--["1","2"]----------->

**********************************************

--------------{a: null}--["1","2"]----------->
                .scan(scanObject)
------------------{a:['1','2']}-------------->
and
-----------------{b: null}--"3"-------------->
                .scan(scanObject)
---------------------{b: 3}------------------>