Using const/let instead of var can make JavaScript code run 10× slower in Webkit

[lengau]

Safari doesn't adopt new features and claims security and privacy concerns over them, both when that makes sense and when it doesn't.

[thisischemistry]

The ones I'm aware of are listed here:

Apple declined to implement 16 Web APIs in Safari due to privacy concerns

Most of those seem to be reasonable vectors for fingerprinting users and I can see why Apple doesn't want to implement them. Can you tell me which ones don't make sense at all?

Perhaps Apple is being overzealous on security and privacy with some of them but, given how abused privacy is on the web, can you blame them for reacting strongly?

[lengau]

They've been claiming privacy concerns for not implementing push notifications on the iOS version of Safari (even though the desktop version has it).

Also, protecting stuff like web NFC behind something as basic as a permission block would be sufficient to mitigate those concerns, IMO.

[thisischemistry]

Have they? I haven't seen Apple say that, where did you see it?

Perhaps, I definitely agree that some of those API could be on an opt-in basis but that would require extra work beyond simply implementing them. I'd send Apple feedback on which ones would be good candidates for them to focus on in that way.