promise object in windows store app
DESCRIPTION
Promise in WinJS is an object, which ensure the app to run smooth without waiting for long running XHR call by using its asynchronous capability.TRANSCRIPT
Promise Object
Presenter: Nirmal Hota, Mindfire SolutionsDate: 21/02/2014
About MeMCTS : .NET Framework 4, Web ApplicationsMCTS : MS Dynamics CRM 2011 Customization and ConfigurationMCTS : Microsoft Dynamics CRM 2011 ApplicationsTCAD : Titanium Certified Application Developer
MS Dynamics CRM, Commerce Server, .Net, WinJS, PhoneGap, Titanium, Xamarin
My Key Skills
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Contact me in :Email : [email protected] | [email protected]
Agenda
>> What is a promise
>> How it works
>> Advantages of promise
>> Real life implementation (Demo)
>> Q & A
>> Some frequently used methods
What is a promise
>> Schedule work for future
>> Asynchronous programming approach
>> Runs in background thread
>> Foreground works without blocking
>> Methods exposed by convention ends with “Async”
How it works
Application
Give me stuffs (via XHR call)
Move N
ext
Promises to get back
Search
I will manipulate the stuff if I get it
Here is your StuffGot it :)
Let's manipulate
Some frequently used Methods
>> then : Allows to define tasks to be done after promise fulfilled.
>> done : Allows to define tasks to be done after promise fulfilled.
>> any : Allows to define tasks to be done after any of the task performed among a set of promises.
>> join : Allows to define tasks to be done after all of the tasks performed among a set of promises.
>> cancel : Allows to cancel an in progress promise
then vs done>> Both of them are used after the completion of promised task
>> Both the methods takes the same kind of parameters completed, error and in progress handlers
>> “then” returns a promise object where as “done” returns an undefined
>> In case any exception occurred in the promised block, “then” puts the error in the promise object and return it to outside. But “done” throws the same to outside as a normal exception. So better place for “done” is at the end of the promise chain
Advantages of promise
>> No blocking of main thread for long running XHR calls. This can be handled in the background
>> Ability to define the tasks after a long running XHR is over
>> Can chain multiple calls
>> Tasks can be defined to be done after the completion of multiple parallel processes or any process out the set processes
Real life implementation
Demo
Question and Answer
Thank you
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