Let's enable Temporal by default

[jasnell]

What is the problem this feature will solve?

The Temporal API is nearing completion in TC39 and is largely stable. It is not turned on by default in V8 just yet until it reaches stage 4 but platforms are starting to enable it by default. We ought to be able to go ahead and enable it by default in main

What is the feature you are proposing to solve the problem?

Enable Temporal by default but still marked as experimental

What alternatives have you considered?

No response

[ljharb]

It would probably be wise to wait until it's been fully shipped unflagged on the web for a bit - maybe for node 25?

[jasnell]

Either way. I'm going to prepare a PR but it's fine to let it sit for a bit

[aduh95]

On one hand, I can't wait for Temporal to be available, but on the other hand, I can wait and use the polyfill a while longer. So far the experience of enabling flagged features of V8 has been mixed (TLA was a success, the import assertions syntax not so much); given this is fully polifillable, I'm not sure it's worth the risks (although I reckon the risks are very mild at worst).

[targos]

Can someone link to the tracking issue in V8 so we have some information on the progress of the implementation there?

[targos]

I wonder if it passes the existing test262 tests for Temporal.

[aduh95]

https://issues.chromium.org/issues/42201538

[jasnell]

Yep, I'm fine with waiting a bit but I wanted to at least get it on the radar here. I'm not in any rush to merge it. V8's test coverage on this is currently hovering around the 75% mark but that is expected to increase significantly in the coming couple of months. My current thinking is that we can let the PR sit and look at merging it still as experimental after 24.0.0 is cut in April with a flag to disable it.