A promise provides a mechanism to schedule work to be done on a value that has not yet been computed. It is a convenient abstraction for managing interactions with asynchronous APIs.
For more information about asynchronous programming, see Asynchronous programming. For more information about promises in JavaScript, see Asynchronous programming in JavaScript.
For more information about using promises, see the Promise sample at Windows Store app samples.
Syntax
var promise = new WinJS.Promise(init, onCancel);
Parameters
- init
-
Type: Function
The function that is called during construction of the promise. The function is given three arguments (complete, error, progress). Inside this function you should add event listeners for the notifications supported by this value.
- onCancel
-
Type: Function
The function to call if a consumer of this promise wants to cancel its undone work. Promises are not required to support cancellation.
Requirements
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Minimum supported client | Windows 8 [Windows Store apps only] |
|---|---|
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Minimum supported server | Windows Server 2012 [Windows Store apps only] |
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Namespace |
WinJS |
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Library |
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See also
Build date: 12/5/2012
