Issue 3862 - Added EventEmitter.listeners()

Issue 3862 - Added EventEmitter.listeners()

[Sebastian Noack, 2016-03-24 11:07:13]

https://codereview.adblockplus.org/29339038/diff/29339039/lib/events.js
File lib/events.js (right):

https://codereview.adblockplus.org/29339038/diff/29339039/lib/events.js#newco...
lib/events.js:87: listeners: function(name)
node.js has that method as well. We need it to reuse EventEmitter to implement
messaging.Port. Currently, in adblockpluschrome we access the private property
_listeners directly which isn't great and requires some duplication, in
particular if we want to slice the array to allow adding/removing listeners from
a listener function.

[kzar, 2016-03-24 11:29:53]

https://codereview.adblockplus.org/29339038/diff/29339043/lib/events.js
File lib/events.js (right):

https://codereview.adblockplus.org/29339038/diff/29339043/lib/events.js#newco...
lib/events.js:102: let args = [];
Any reason why you now create the args array even when there are no listeners?

[Sebastian Noack, 2016-03-24 11:33:27]

https://codereview.adblockplus.org/29339038/diff/29339043/lib/events.js
File lib/events.js (right):

https://codereview.adblockplus.org/29339038/diff/29339043/lib/events.js#newco...
lib/events.js:102: let args = [];
On 2016/03/24 11:29:53, kzar wrote:
> Any reason why you now create the args array even when there are no listeners?

To keep the logic simple. Before we had to handle the case of this._listeners
being undefined anyway, otherwise slicing or iterating over it would fail
anyway. So I created the args array in the same code path. This check however
isn't necessary anymore, and checking for listeners.length instead would be
redundant, but just a micro-optimization.

[kzar, 2016-03-24 11:35:59]

LGTM

https://codereview.adblockplus.org/29339038/diff/29339043/lib/events.js
File lib/events.js (right):

https://codereview.adblockplus.org/29339038/diff/29339043/lib/events.js#newco...
lib/events.js:102: let args = [];
On 2016/03/24 11:33:27, Sebastian Noack wrote:
> On 2016/03/24 11:29:53, kzar wrote:
> > Any reason why you now create the args array even when there are no
listeners?
> 
> To keep the logic simple. Before we had to handle the case of this._listeners
> being undefined anyway, otherwise slicing or iterating over it would fail
> anyway. So I created the args array in the same code path. This check however
> isn't necessary anymore, and checking for listeners.length instead would be
> redundant, but just a micro-optimization.

Fair enough I guess

[Wladimir Palant, 2016-04-04 13:01:27]

LGTM