feat!: support safari14 by default for wider ES2020 compatibility

[lgarron]

Description

From #9062, it sounds like the goal is to support ES2020 by default. However, the browser list was set to safari13, which means that big ints (an ES2020 feature) produced an error by default.

This PR updates from safari13 to safari14 (released September 2020) to support that.

Additional context

I help maintain a library with a feature that uses big ints. We'd like to recommend a "batteries included" bundler to use for our library, but Vite 3 requires this change to work out of the box.

(I've tested that this one-line change resolves the build error for big ints when using our library with Vite 3.)

What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

Before submitting the PR, please make sure you do the following

• Read the Contributing Guidelines.
• Read the Pull Request Guidelines and follow the Commit Convention.
• Check that there isn't already a PR that solves the problem the same way to avoid creating a duplicate.
• Provide a description in this PR that addresses what the PR is solving, or reference the issue that it solves (e.g. fixes #123).
• Ideally, include relevant tests that fail without this PR but pass with it.

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[patak-dev]

Hey @lgarron, thanks for the PR.

For reference, we updated Safari from 13.1 to 13 so we still transpile nullish coallesing in:

• feat!: relative base #7644

IIUC safari 13.1 still doesn't support big int (https://caniuse.com/?search=BigInt), so you should be getting the same problem in 2.9 if only setting the es2020 target.

Would you check that? The other option is to leave Safari as 13 and downgrade Firefox to 71 (also not transpiling nullish coallesing).

We have planned a v3 release today so changing to Safari 14 isn't an option for Vite v3. But Vite v4 will be released in a few months after upgrading to rollup v3, so we will have another opportunity to review the targets there.

[lgarron]

For reference, we updated Safari from 13.1 to 13 so we still transpile nullish coallesing in:

I see, that's more of a hack than actually intended to declare the target Safari compat?

IIUC safari 13.1 still doesn't support big int (https://caniuse.com/?search=BigInt), so you should be getting the same problem in 2.9 if only setting the es2020 target.

Yeah, I had issues with Vite 2, and it sounds like the answer from #9062 is "use Vite 3".

We have planned a v3 release today so changing to Safari 14 isn't an option for Vite v3. But Vite v4 will be released in a few months after upgrading to rollup v3, so we will have another opportunity to review the targets there.

Hmm, that sounds like the answer is "actually, use Vite 4".

I guess if it's too late to add default big int compat to Vite 3, then we just won't be able to recommend it as a bundler, and have to document caveats. I can certainly understand if shipping Vite 3 soon is more important than wider ES2020 compat, though.

Would you check that? The other option is to leave Safari as 13 and downgrade Firefox to 71 (also not transpiling nullish coallesing).

Do you mean firefox71 + safari14 (not 13)? I can confirm that this covers enough ES2020 features to support our library.

[lgarron]

Did you mean this?
(+ undoing the other change)

Suggested change

	'firefox78',
	'firefox71', // transpile nullish coalescing

[patak-dev]

I mean reverting to safari 13.1, as you said this issue wasn't present in v2.9 + es2020. But I think safari 14 is needed

[lgarron]

Yeah, Safari 13.1 wouldn't help for compat in this case: https://caniuse.com/bigint

[patak-dev]

I mean firefox71 + safari13.1, but I dont see how that would help.

We could use Do you mean firefox71 + safari14 in v4, and during the next months better document the config needed as you suggest

[lgarron]

I mean firefox71 + safari13.1, but I dont see how that would help.

Yeah, that wouldn't. 😔

We could use Do you mean firefox71 + safari14 in v4, and during the next months better document the config needed as you suggest

Yeah, I appreciate that goal, but unfortunately we really want to recommend a bundler that works out of the box, with no configuration. We can't hang our hat waiting on a future Vite 4 release, so we'll probably have to figure out another choice.

Thanks for the due consideration!

[lgarron]

Interestingly, it looks like esbuild might allow overriding the target for specific features.

So it might be possible to replace the workaround with: "nullish-coalescing": false

Or it would work for us to set "bigint": true.

[lgarron]

Interestingly, it looks like esbuild might allow overriding the target for specific features.

So it might be possible to replace the workaround with: "nullish-coalescing": false

Or it would work for us to set "bigint": true.

Here's an approach that avoids Safari 14 while explicitly setting those two:

main...lgarron:vite:esbuild-supported-features

It compiles, but I still haven't managed to figure out how to test it, though.

[bluwy]

We also need to update the docs at

vite/docs/guide/build.md

Line 11 in 892916d

- Safari >=13

Besides that LGTM!

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I'm probably on the side that we don't need to lower any version so that nullish coalescing gets transpiled. It's supported by most browsers since Q1 2020. If there's a compelling request after 4.0 we could still do so too in a non-breaking way.

[patak-dev]

I agree with your call @bluwy. For reference https://caniuse.com/?search=nullish%20coalescing. This should help also reduce some projects' size in prod, which is great.