Deferred has no always() method

[bill]

The doc for Promise says that it has an always() ethod, but it doesn't.

I saw this when trying to update Tree to use this.pendingCommandsDeferred.always() rather than this.pendingCommandsDeferred.then(), but the problem can be reproduced simply by:

require(["dojo/Deferred"], function(Deferred){ console.log( (new Deferred()).always ); })

Also, the API doc marks the callback parameter as optional, but presumably it's not. always() is meaningless, right?

[bill]

In [29577]:

Use always() not then(), so that new commands keep executing even if a previous command failed. (Note that always() method is on Promise but not on Deferred). Refs #15902 !strict.

[Mark Wubben]

Utility methods are on promises, not on the deferreds. You could use this.pendingCommandsDeferred.promise.always().

The callback is optional so far as that no errors are thrown if it's missing, but obviously it'd mean the resulting promise won't be resolved with any value.

[bill]

Surely the callback is mandatory. What exactly would always() with no argument do?

[Mark Wubben]

Following <​https://github.com/dojo/dojo/blob/master/Deferred.js#L32>, it's effectively a noop that just creates a new promise. Like calling deferred.then().