[CLEANUP] Remove IE11 support

[simonihmig]

Remove IE11 deprecation warnings and tests, as per RFC 685.

Removing the transpilation for IE11 unveiled some mismatch of other transpilation settings vs. the testing environments:

• Safari tests were failing, as babel settings were "last 2 Safari versions" (which according to latest caniuse data is 14.1 + 14), but BrowserStack was configured for Safari 12.1. Changed this to 14.
• node tests were as well failing with some syntax errors. Added a node: 'current' setting to targets, but only when running node tests, to keep browser tests untouched.

[simonihmig]

Hm, the CI UI seems to be somehow broken here, indicating that there is a pending "Browserstack Tests (Safari, Edge, IE11)" job, which actually does not exist (has been renamed, and the renamed one exists and is green). When you click on the "Checks" tab, all jobs are listed as expected and green. 🤔

[simonihmig]

Btw, there are probably one or two more iterations possible here, to remove remaining IE11 cruft, like workarounds for missing APIs. But I wanted to keep the scope here to the most essential changes.

[simonihmig]

Not sure if we actually need to keep these two separate lists, as they are mostly the same now (with Edge basically being Chrome)?

[SergeAstapov]

@simonihmig this is definitely 👍!

However, per PRF #685 (and Ember.js Browser Support Policy ultimately) Safari 12 is supported by Ember.js.

I wonder if CI still should be configured for Safari 12?

[simonihmig]

However, per PRF #685 (and Ember.js Browser Support Policy ultimately) Safari 12 is supported by Ember.js.

Oh, right, good catch! Thanks!

I did not intend to implement that RFC fully here, more to focus on getting rid of IE for unblocking further refactorings and other semi-related PRs (#19552). But at least we shouldn't cause regressions in test coverage here.

So I reverted the BrowserStack config change, and added Safari 12 to targets, which now also makes the Safari tests pass again!

Uh, blueprint tests are failing somehow, but that seems unrelated

[rwjblue]

Due to some complications with 3.27's migration to use real modules (and the resulting massive number of deprecations being triggered) we are not 100% certain (yet) that 4.0 will be the version just after v3.28.

In order to move ahead with v4.0 cleanup efforts (like this one), I've pushed a new branch that can serve as the target for breaking change PR's: https://github.com/emberjs/ember.js/tree/v4-cleanup.

I've updated this PR to target that branch, can you rebase against that branch and push an update?

Expand for an example of the commands needed for that rebase.

# starting from this PR's branch

git fetch origin
git rebase origin/v4-cleanup

# fix any conflicts

# push the rebase
git push -f

Those steps should be roughly what you need, but might need some tweaks based on your local repository setup (e.g. if you don't use origin for the main emberjs/ember.js repo you might have to use another remote name there).

Thank you for helping us push things forward!

[simonihmig]

Done