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Asynchronous execution chain based on collections API with wrappers around DHTML DOM API, jQuery and XML+XSLT+XPATH

JS module is published in NPM


   DefineScenario( arr ).a().b()

Is used for scenario creation which could be triggered with own dataset more than once later via .start(data) method.

  • wraps methods of given object/collection elements
  • wrapper on call saves the CallDeclaration into call list of previous call


is a signature of method call with CallParameters. In dot call chain each method with parameters saved as CallDeclaration.

It holds wrappers in prototype for all methods of object given to DefineScenario( dataDefinition ), which is used for sub-scenario creation.

   let subA = DefineScenario( dataDefinition ).a();

In given sample subA is split into two sub-chains which will be run in parallel.

   DefineScenario( dataDefinition ).a()

Each method( a,b,c,x,y,z ) wrapper in sample returns own CallDeclaration allowing further call chain(s) creation.

First in chain

   DefineScenario( dataDefinition )

DefineScenario() returns CallDeclaration object which does not have other attributes except of list of following CallDeclarations.


During scenario execution the method is called for each wrapped object with parameters defined during declaration or computed in run time:

  • usual parameters are passed in run time by value
  • the named or back reference in Call Graph
  • computed by callback for each wrapped object at runtime
   let abc = i=> ({ v: ()=>i, a: x=> x+i,b: x=> x+i,c: (x,y,z)=> x+y+z+i }) // returns object with  v, a(), b(), c() members
   ,   arr = [ abc(1), abc(2), abc(3) ];
   DefineScenario( arr ).a(10).b(20); 
   DefineScenario( arr ).a(10).b(20).c( CallRef(-1), CallRef(-2), CallRef(1) ); // arr[i].c( 20+i, 10+i, 10+i )
   const cb = ( el, index, collection, callTree )=> index  ;   // callback evaluates last call as c(i)
   DefineScenario( arr ).a(10).b(20).c( CallRef( cb ) );       // arr[i].a(10).b(20).c( i )

Method name

In CallDeclaration used for invoking the wrapped object method.

Call Graph

   DefineScenario( arr ).a(10).b(20).set();

In the sample above array elements are served in parallel:

                              / abc(1) » a(10)  == 11 » b(20) == 21 \
   [ abc(1), abc(2), abc(3) ] - abc(2) » a(10)  == 12 » b(20) == 22 - [21,22,23]
                              \ abc(3) » a(10)  == 13 » b(20) == 23 /

The .set() method wait for all chains finished before result of last call saved into new collection. Further collection objects are numbers so it does not make a


DefineScenario does not run the chain itself, it needs to be executed either by direct invoking of .start(data) or via AsyncChain helper API.

   const scenario= DefineScenario( arr );
   const callStack1 = scenario.start( arr );// same data is used as for declaration as for execution
   const callStack2 = scenario.start( arr2 ); // another data set

While CallStack became available immediately upon start(), it executed asynchronously and could be interrupted or destroyed at any time. It supports the activation( pause,start,restart ) and debug( break, pause, resume,callstack ) APIs.


combines declaration and execution in single call:

   AsyncChain( arr ).a(10).b(10);

is same as two calls:

   const scenario= DefineScenario( arr ).a(10).b(20);
   scenario.start( arr );