WP 6.2 breaks post edit screens, site customizer and widget editor in Safari 13.1.2

[remcokalf]

Description

After updating WP to 6.2, all post-edit screens, the site customizer, and the widget editor are all white screens in Safari 13.1.2. Attached are all JS errors in the console.

Version 6.1.1 was working perfectly fine, I work all day in this Safari version (in the code editor of Gutenberg) without issues.

I understand this is a pretty old version of Safari, and fully expect this ticket to get cancelled because of it not being support. Also that I can use Firefox/Chrome etc.
However, this is the max version in High Sierra and my Mac Pro does not go beyond High Sierra. And I like working in Safari.

So I have the slight hope that by reporting these issues here, they may be fixable with minor effort, thus keeping support for older Safari versions.

Reported in trac here, was referred to this repo.

https://core.trac.wordpress.org/ticket/58032

Step-by-step reproduction instructions

1. In Safari 13.1.2 go to a Post Edit screen, the site customizer or widget editor
2. White screen

Screenshots, screen recording, code snippet

Errors in Console in post edit screen:

Errors in Console in Site customizer:

Errors in Console in Widget editor:

Environment info

WP 6.2
Safari 13.1.2 on macOS High Sierra

Please confirm that you have searched existing issues in the repo.

Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

Yes

[mrfoxtalbot]

I can confirm I am getting what you describe when using Safari 13.1

[youknowriad]

That version of safari is actually not supported anymore. This is our official browser list config https://github.com/WordPress/gutenberg/blob/trunk/packages/browserslist-config/index.js

This means that we support browsers from the latest 2 versions of each major browser and any browser that has more than 1% usage. Safari 13 has 0.17% usage I think so there's most likely some JS syntax that is not transpiled to a code that is understandable by that browser.

[youknowriad]

We can of course update that list to say latest 4 versions of Safari but that probably requires a larger discussion.

[remcokalf]

I don't believe the whole Gutenberg editor was working properly in Safari 13.1.2. But at least you could view your content, and use the Code editor to edit it.

[youknowriad]

@remcokalf The problem here is that it's probably not a single feature but several places using some JavaScript syntax that is not supported in Safari. In previous versions, that syntax was transpiled but since the browser is not supported, the syntax is not transpiled anymore. It would be good to know exactly which syntax is breaking here though to see if it's something we used everywhere or just some very specific thing.

[octoxan]

It doesn't work in Safari 16.4 either.

[youknowriad]

@octoxan it works perfectly for me in that version, do you mind sharing the error and more details about your issues?

[Mamaduka]

What's the status on this issue? Do you know if this is still relevant, or should we close it?

[ntsekouras]

@youknowriad is right about the supported versions and right now the Safari supported versions are above 18. Let's close this one.