Things to do when we drop IE11 support someday

[jelbourn]

Writing this issue to keep track of the things we can do / drop once we no longer support IE11. This issue is mainly for record-keeping. Eventually dropping will likely be based on Microsoft ending support for Windows 7, which is currently slated for January 2020.

• Incorporate CSS custom properties into theming
• Drop extra code for sticky positioning and just use position: sticky
• Use IntersectionObserver for overlay positioning
• Use WeakSet instead of WeakMap<T, boolean>
• Second parameter to classList.toggle
• Use element.remove() instead of element.parentNode.removeChild(element)
• Start using CSS Grid, potentially deprecating mat-grid-list
• Start using KeyboardEvent.key / KeyboardEvent.code (re-evaluate cdk/keycodes)
• Explore possibly using native Shadow DOM
• Remove re-implementations of matches and closest
• Get rid of IE-specific cases in InteractivityChecker
• Explore clip-path as a means of custom shapes for components
• Remove IE11-specific fallback animation in mat-spinner
• Can use unset CSS value

[lqc]

I would like to comment on the keyCode part of the issue.

KeyboardEvent.key is widely supported. From what I could tell, Edge has fixed issues with key names (not sure about AltGr problem) and the same could be done in IE11 with a simple shim.

Would you consider going forward with dropping use of keyCode and document the shim for anyone that uses IE11 (similar to classlist, etc.) ?

[jelbourn]

Our current stance is that we don't want to require users to polyfill anything for IE11 (that isn't already needed by Angular itself).

[mina-skunk]

I think you'd want to use code not key once you drop IE11 because code represents the physical key and key is the printable representation.

[moniuch]

Now that the IE support is officially gone, I believe the keycode-related tickets (closed around 2018 and 2019) can be reopened.

[dzonatan]

It's getting more and more difficult to keep up with the use of deprecated keyCode property.
For example, a quite popular library called user event from testing-library does not fill the keyCode event since v14.0.0 (2022-03-29). Of course, there are always ways to patch something to make everything work but maybe it's time to move forward and switch away from using keyCode in the CDK? Maybe the community can help with this? I see there was an attempt some long time ago that was closed, which is understandable, at that time.