Transparently applies callbacks to values and/or promises.
Accepts promises but also transparently handles non-promises. If no callbacks are provided returns a promise, regardless of the initial value. Foreign promises are converted.
If callbacks are provided and the initial value is not a promise, the callback is executed immediately with no error handling. Returns a promise if the initial value is a promise, or the result of the callback otherwise.
| Parameter | Type | Description |
|---|---|---|
| valueOrPromise | undefined | Either a regular value or an object with a |
| callback | Function |
Optional Callback to be invoked when the promise is resolved, or a non-promise is received. |
| errback | Function |
Optional Callback to be invoked when the promise is rejected. |
| progback | Function |
Optional Callback to be invoked when the promise emits a progress update. |
Promise, or if a callback is provided, the result of the callback.
See the dojo/when reference documentation for more information.