Remix causes syntax errors in iOS 11

[jfsiii]

What version of Remix are you using?

1.8

Steps to Reproduce

Visit a Remix app in iOS 11

e.g. create one with npx create-remix@latest and browse it on https://browserstack.com

Expected Behavior

The site looks and functions as normal. No JS errors in the console

Why do I expect this?

https://remix.run/docs/en/v1/guides/browser-support says

Remix only runs in browsers that support ES Modules.

The linked page shows iOS on Safari supports ES Modules as of version 11.0

Actual Behavior

I'm having a hard time finding an 11.0 browser for testing but there are syntax errors in both 11.2 and 11.3

iOS 11.3

JS Syntax error in the console (from optional chaining?)

I believe this is from the optional chaining operator (which [isn't in Safari until 13.4](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Optional_chaining#browser_compatibility))

https://github.com/search?q=repo%3Aremix-run%2Fremix+%22%3F.data%22+path%3A%2F%5Epackages%5C%2F%2F&type=code&l=packages%2F

https://github.com/search?q=repo%3Aremix-run%2Fremix+%22%3F.formMethod%22+path%3A%2F%5Epackages%5C%2F%2F&type=code&l=packages%2F

iOS 11.2

JS Syntax error in the console (from optional catch binding and spread in object literals?)

I believe this is from the use of optional catch binding

which isn't available until iOS 11.3

It's not shown in the above screenshot, but in my own app I've seen this error

Unexpected token: '...'. Expected a property name.

I believe this is from using spread in object literals which also isn't supported until 11.3

Suggested / requested changes

I'm not sure if Remix should change the source files to avoid using these patterns or do transforms to change the distributed code, but it should be possible to use Remix in iOS 11.0 without syntax errors.

Also, is there a way to add tests/checks for this to prevent regressions?

[machour]

Thank you for the detailed report. This is already tracked in #1901

[jfsiii]

@machour I've seen that ticket (I mentioned this there)

However, that ticket references iOS 12 and some newer features than this ticket. To achieve the documented browse support Remix needs to run in iOS 11.0.

This ticket mentions more syntax errors and the and the places in remix which cause them. Perhaps that ticket could be updated to include the information from here?

[machour]

@jfsiii we have your latest comment there + a reference to this issue, it should be ok.
Team is planning on adding support for browserlist, which should allow everyone to fine-tune compatibility 👌🏼