Control asynchronous processes by multiple callbacks using Deferred

To control the synchronous or asynchronous flow, there may be more methods but we will do this by multiple callback mechanism using deferred and promise object.

In order to use this mechanism first we need to have an understanding of deferred and promise object.
Here we will use a promise with a deferred object.
A promise is a placeholder for a result, which is initially unknown. While a deferred represents the computation that results in the value. Every deferred has a promise, which functions as a proxy for the future result.
A promise is a value returned by an asynchronous function, but a deferred can be resolved or rejected by its caller which separates the promise from the resolver. Continue reading


Using WinJS.Promise.Join-Executing a task after others finishes

WinJS.Promise.join is a method being exposed by the Promise object to deal with multiple promise objects execution.

This is a live scenario when I have received a task which will call a set of web services and perform certain action after the completion of all web services execution in an asynchronous mode.

HTML file content Continue reading

WinJS.Promise – My Experiment to create some delay using loop

WinJS.Promise is a class, which supports the asynchronous programming model. Upon the execution, program control executes the promise class and proceeds to the subsequent statement to execute. But it keeps track of the execution point to which control needs to get back after the promised function finished its execution.
A question was banging my head, whether I can create my own delay to the promise object and invoke Then/Done.

I tried 2 kind of exercises. But in both the exercise I had the HTML page common.

Exercise #1
Used the below code to create a delay by executing a long loop in an external method and returning a promise object from it. So that on completion, I can call Then method to do some task. Continue reading