escalator

a flow-control class for javascript (nodeJS & browser)

DESCRIPTION

in async environments - we do love them - there are times when you need to make sure foo is run after bar in all cases. for our VisualWeb framework we thus developed a object/class called escalator that allows us to write sequential code.

• this code is part of the VisualWeb Project by

• LinkCloud ( http://www.mylinkcloud.com )

• ViSERiON UG (haftungsbeschraenkt) ( http://www.viserion.com )

• K!Lab GmbH ( http://www.klab-berlin.com )

• MIT license.

• AUTHOR: Toni Wagner @itsatony

USPs

• escalator offers DELAYS between steps. These are handy to make your app more response during cpu/load intensive code sequences. For example timeouts are a good idea to update upload/downloaf/progress bars
• escalator offers setting of code-SCOPE PER STEP, thus enabling you to control the memory environment your steps are run in.
• escalator offers a CONSTANT NAMESPACE, actually its own namespace, which is made available (passed as an additional call parameter) to every step. Thus, exchange of data between steps is super-easy and straightforward.
• escalator objects can PERSIST with fully running and debugging info if you want that.
• escalator offers a debug/logging mode that will record the time each step takes. very handy for performance optimization and error tracing
• escalator wraps each step-call into a try-catch and allows you to define the errorhandler.
• escalator steps can control the flow of efficiently, even stop the complete escalator with a message.

DEPENDENCIES

• dependencies were removed ... this is totally independent now .
• it should integrate into NodeJS on the server-side or any browser-side with javascript enabled.

TESTS

• none yet ;(

VERSIONS

• • v0.2.8 added onError checking and upon catchError onError will be called. if not there the escalator finishes.

•  - v0.2.2	fixes to default add values		18.12.2013	
  

•  - v0.2.0	initial public release		15.11.2012	
   	- bug fixes
   	  - better error handling of steps
     	- optional try-catching of steps (allows for js engines to run optimizations if turned off)
  

• v0.1.0 initial public release 08.05.2012
  • removed dependencies
  • enabled using the same file for client- and nodeJS server-side implementation

URLs

• blogpost: http://coffeelog.itsatony.com/escalator
• github: https://github.com/itsatony/escalator

CODE EXAMPLES

• 1 - three steps, different configs

 	var someVar = 'hello';
 	var firstStep = {
        id: 'myFirstStep',
        priority: 10,
        executor: function(next, thisEscalator) {
            someVar = 'hello too'
            next();
        }
    };
    var secondStep = {
        id: 'mySecondStep',
        priority: 20,
        delay: 10,
        parameters: [ someVar ],
        scope: this,
        executor: function(somethingWePassedIn, next, thisEscalator) {
            console.log(somethingWePassedIn);
            thisEscalator.anotherVariable = 42;
            next();
        }
    };	
    var lastStep = {
        priority: 22,
        executor: function(next, thisEscalator) {
            console.log(thisEscalator.anotherVariable);
            next();
        }
    };
    var myDemoEscalator = new escalator(
        'demoEscalator',
        [ firstStep, secondStep, lastStep ]
    ).start();