Minimum browser versions required for new features:

• ?? nullish operator: Chrome 80, Edge 80, Firefox 72, Opera 67, Safari 13.1, iOS 13.4
  • Note: Caniuse differs from MDN and incorrectly shows Chrome 85+. Confirmed using Browserstack that Chrome 80 supports this.
• ?. optional chaining operator: Chrome 80, Edge 80, Firefox 74, Opera 67, Safari 13.1, iOS 13.4
• String.prototype.matchAll: Chrome 73, Edge 79, Firefox 67, Opera 60, Safari 13, iOS 13
• BigInt literals: Chrome 67, Edge 79, Firefox 68, Opera 54, Safari 14, iOS 14
• Promise.allSettled: Chrome 76, Edge 79, Firefox 71, Opera 63, Safari 13, iOS 13

Overall: Chrome 80, Edge 80, Firefox 74, Opera 67, Safari 14, iOS 14

?? nullish operator: Chrome 80, Edge 80, Firefox 72, Opera 67, Safari 13.1, iOS 13.4
Note: Caniuse differs from MDN and incorrectly shows Chrome 85+. Confirmed using Browserstack that Chrome 80 supports this.

Caniuse shows data for nullish coalescing assignment (x ??= y), which I assume is due to a devUX consideration on their part. The assignment operator was introduced in ES2021: https://tc39.es/ecma262/2021/#sec-assignment-operators-static-semantics-early-errors (so next version)... So SD0001 is correct, but Caniuse is also kind of correct :)

Something to keep in mind in this part: CodeMirror: update JavaScriptValidator to allow ES2020, as ??= would have to be considered invalid syntax.

In T429706#12111832, @SD0001 wrote:

Note: Caniuse differs from MDN and incorrectly shows Chrome 85+. Confirmed using Browserstack that Chrome 80 supports this.

In T429706#12189328, @Nux wrote:

[…] Caniuse shows data for nullish coalescing assignment (x ??= y), which I assume is due to a devUX consideration on their part. […]

This is a link to the CanIUse entry for wf-nullish-coalescing which refers to group of features. This is not a decision by CanIUse. It is from the Baseline Web Features dataset, which is one of the two datasets that CanIUse includes in its results. It simply joins two MDN features together.

When you search for "nullish", there are several results and the second result is for ??:

Now that the T434032 is closed as a "duplicate" of this active task, I can't help wondering how this active task will affect macOS Safari 13 and iOS Safari 15.

In T429706#12197006, @gh87 wrote:

...I can't help wondering how this active task will affect macOS Safari 13 and iOS Safari 15.

According to CanIUse.com, ES2020 is fully supported in Safari 14.1+, so we'll probably drop Safari 12 and 13 when we next raise the JS requirement.

In T429706#12197040, @Mr._Starfleet_Command wrote:

In T429706#12197006, @gh87 wrote:

...I can't help wondering how this active task will affect macOS Safari 13 and iOS Safari 15.

According to CanIUse.com, ES2020 is fully supported in Safari 14.1+, so we'll probably drop Safari 12 and 13 when we next raise the JS requirement.

Any other tool besides CanIUse.com?

Also, may I please propose extending some further support for (macOS) Safari 13 on macOS 10.13 High Sierra, the final version for a unibody iMac 2009–11 and polycarbonate unibody macBook 2009–10? Indeed, I hate to drop Modern (Grade A) support for Safari 13 just because ES2020 is not supported on Safari 13

@Mr._Starfleet_Command Just in case, list of iMac and macBook models for you to look at.

In T429706#12197099, @gh87 wrote:

Any other tool besides CanIUse.com?

For me, CanIUse.com is the easiest way to check cross-browser support for several features at once, particularly ES versions. MDN Web Docs is the other resource I use, although I'm sure there are other good ones out there.

Also, may I please propose extending some further support for (macOS) Safari 13 on macOS 10.13 High Sierra, the final version for a unibody iMac 2009–11 and polycarbonate unibody macBook 2009–10?

We only just raised the JS requirement to ES2019 within the last week, so the earliest we might fulfill this task is some time next year, so not an immediate worry.

Indeed, I hate to drop Modern (Grade A) support for Safari 13 just because ES2020 is not supported on Safari 13

The only practical impact is that Safari 13 won't receive the Modern layer anymore (JS enhancements). MediaWiki sites will still be accessible and usable for the most part. Is there a particular reason you think we need to continue to fully support Safari 13 for much longer?

The only practical impact is that Safari 13 won't receive the Modern layer anymore (JS enhancements). MediaWiki sites will still be accessible and usable for the most part. Is there a particular reason you think we need to continue to fully support Safari 13 for much longer?

For all I know, page views from macOS Safari 13 aren't that stellar. Indeed, the stats for that version been 0.009%, compared to stats from iOS Safari 13.

Also, macOS High Sierra has been the latest and final version for certain iMacs and macBooks.

Well, those still using macOS 10.12 Sierra, 10.13 High Sierra, or 10.14 Mojave may have to migrate to Firefox ESR 115, whose official support is supposed to end in March 2027. (Sources: Wikipedia, Mozilla)

I'm not asking for a lifetime or indefinite Modern support for macOS Safari 13. Rather perhaps give macOS Safari 13 either six more months, one more year, or.... some time until the devs are ready to give up Modern support for macOS Safari 13.

MacOS Safari 13 may still enjoy Basic support when its Modern one ends, but I dunno how prioritized issues about macOS Safari 13 have been lately. Perhaps give macOS users some time to shift from macOS Safari to Firefox ESR or to change from macOS 13 to a later macOS version. Or...

In T429706#12197156, @gh87 wrote:

Well, those still using macOS 10.12 Sierra, 10.13 High Sierra, or 10.14 Mojave may have to migrate to Firefox ESR 115, whose official support is supposed to end in March 2027. (Sources: Wikipedia, Mozilla)

Safari 13 is also long past the end of its official support. If people are okay using that they should be okay using Firefox ESR 115. I didn't think this is a convincing argument to hold back the entire site for the sake of 0.009% of readers (most of whom are just reading and not using modern features).

@Ahecht Firefox 115 has given 0.143% viewership, FWIW.

In T429706#12197156, @gh87 wrote:

...perhaps give macOS Safari 13 either six more months, [or] one more year...

Did you read my comment above, where I said, "the earliest we might fulfill this task is some time next year, so not an immediate worry"?

I ask again: Is there a particular reason you think we need to continue to fully support Safari 13 for much longer? (For example, do you perhaps use Safari 13? Or is there some other reason?)

In T429706#12197876, @Mr._Starfleet_Command wrote:

Did you read my comment above, where I said, "the earliest we might fulfill this task is some time next year, so not an immediate worry"?

I acknowledge the comment that I read. Perhaps I should've replied that earlier.

I ask again: Is there a particular reason you think we need to continue to fully support Safari 13 for much longer? (For example, do you perhaps use Safari 13? Or is there some other reason?)

I guess I'll find public mac computers using macOS High Sierra before answering any further then

I'm sorry, I still don't quite understand. Probably my fault :)