'KeyboardEvent.keyIdentifier' is deprecated warning in Chrome

[web-padawan]

Description

'KeyboardEvent.keyIdentifier' is deprecated and will be removed in M53, around September 2016. See https://www.chromestatus.com/features/5316065118650368 for more details.

This warning is caused by line 182:

transformKeyIdentifier(keyEvent.keyIdentifier) ||

Seems that this should be removed.

[web-padawan]

I'm going to send a PR to fix that warning.
Shouldn't we get rid of the keyIdentifier at all?
/cc @valdrinkoshi

[valdrinkoshi]

I'm afraid it would be a breaking change as other browsers don't support key yet, and the other options (keyCode, charCode) are no better than keyIdentifier...

[samccone]

@valdrinkoshi thoughts on falling back to key Identifier if key is not supported?

[valdrinkoshi]

@samccone that's already happening, see https://github.com/PolymerElements/iron-a11y-keys-behavior/blob/master/iron-a11y-keys-behavior.html#L178

Fall back from .key, to .keyIdentifier, to .keyCode, and then to .detail.key to support artificial keyboard events

[samccone]

correct, but switching the order of the fallback so that .keyIdentifier is lower on the || fall through.
Testing a patch locally now.

[valdrinkoshi]

Unfortunately the warning gets displayed anyways if for example you hit "?" (shift + / key in US keyboard). I think that normalizedKeyForEvent should be converted to something like:

if (keyEvent.key) {
  return transformKey(keyEvent.key, noSpecialChars);
}
if (keyEvent.detail && keyEvent.detail.key) {
  return transformKey(keyEvent.detail.key, noSpecialChars);
}
return transformKeyIdentifier(keyEvent.keyIdentifier) ||
  transformKeyCode(keyEvent.keyCode) || '';

I'll take care of that (there are some tests to be fixed)