dojo/Deferred
Summary
Creates a new deferred. This API is preferred over dojo/_base/Deferred.
Creates a new deferred, as an abstraction over (primarily) asynchronous operations. The deferred is the private interface that should not be returned to calling code. That's what the promise
is for. See dojo/promise/Promise.
Usage
(canceler);
Parameter | Type | Description |
---|---|---|
canceler | Function | Optional
Will be invoked if the deferred is canceled. The canceler receives the reason the deferred was canceled as its argument. The deferred is rejected with its return value, or a new |
See the dojo/Deferred reference documentation for more information.
Properties
promise
Defined by: dojo/Deferred
Methods
cancel
(reason,strict)
Defined by dojo/Deferred
Inform the deferred it may cancel its asynchronous operation.
Inform the deferred it may cancel its asynchronous operation. The deferred's (optional) canceler is invoked and the deferred will be left in a rejected state. Can affect other promises that originate with the same deferred.
Parameter | Type | Description |
---|---|---|
reason | any |
A message that may be sent to the deferred's canceler, explaining why it's being canceled. |
strict | Boolean | Optional
If strict, will throw an error if the deferred has already been fulfilled and consequently cannot be canceled. |
Returns: any
Returns the rejection reason if the deferred was canceled normally.
isCanceled
()
Defined by dojo/Deferred
Checks whether the deferred has been canceled.
Returns: Boolean
isFulfilled
()
Defined by dojo/Deferred
Checks whether the deferred has been resolved or rejected.
Returns: Boolean
isRejected
()
Defined by dojo/Deferred
Checks whether the deferred has been rejected.
Returns: Boolean
isResolved
()
Defined by dojo/Deferred
Checks whether the deferred has been resolved.
Returns: Boolean
progress
(update,strict)
Defined by dojo/Deferred
Emit a progress update on the deferred.
Emit a progress update on the deferred. Progress updates can be used to communicate updates about the asynchronous operation before it has finished.
Parameter | Type | Description |
---|---|---|
update | any |
The progress update. Passed to progbacks. |
strict | Boolean | Optional
If strict, will throw an error if the deferred has already been fulfilled and consequently no progress can be emitted. |
Returns: dojo/promise/Promise
Returns the original promise for the deferred.
reject
(error,strict)
Defined by dojo/Deferred
Reject the deferred.
Reject the deferred, putting it in an error state.
Parameter | Type | Description |
---|---|---|
error | any |
The error result of the deferred. Passed to errbacks. |
strict | Boolean | Optional
If strict, will throw an error if the deferred has already been fulfilled and consequently cannot be rejected. |
Returns: dojo/promise/Promise | instance
Returns the original promise for the deferred.
resolve
(value,strict)
Defined by dojo/Deferred
Resolve the deferred.
Resolve the deferred, putting it in a success state.
Parameter | Type | Description |
---|---|---|
value | any |
The result of the deferred. Passed to callbacks. |
strict | Boolean | Optional
If strict, will throw an error if the deferred has already been fulfilled and consequently cannot be resolved. |
Returns: dojo/promise/Promise
Returns the original promise for the deferred.
then
(callback,errback,progback)
Defined by dojo/Deferred
Add new callbacks to the deferred.
Add new callbacks to the deferred. Callbacks can be added before or after the deferred is fulfilled.
Parameter | Type | Description |
---|---|---|
callback | Function | Optional
Callback to be invoked when the promise is resolved. Receives the resolution value. |
errback | Function | Optional
Callback to be invoked when the promise is rejected. Receives the rejection error. |
progback | Function | Optional
Callback to be invoked when the promise emits a progress update. Receives the progress update. |
Returns: dojo/promise/Promise
Returns a new promise for the result of the callback(s). This can be used for chaining many asynchronous operations.
toString
()
Defined by dojo/Deferred
Returns: String
Returns [object Deferred]
.
© 2005–2017 JS Foundation
Licensed under the AFL 2.1 and BSD 3-Clause licenses.
http://dojotoolkit.org/api/1.10/dojo/Deferred.html