Metadata Reflection API future

[zloirock]

About 8 years ago, after many requests, Metadata Reflection API was added to core-js.

It was not an official JS proposal, but the authors wrote that they wanna present it TC39 IIRC when decorators get the stage 2.

Decorators are now on stage 3, but it was not presented and most likely will not be in the current form.

Now available a new decorators metadata proposal that already reached stage 2, but haven't such helpers.

However, the old Metadata Reflection API is still used in TypeScript output, and I regularly see that core-js helps someone who needs it. It's the reason why I didn't remove it at the previous major release.

core-js follows the old spec that, unlike reflect-metadata library, does not have Reflect.decorate method - that's used in TS-generated code.

Unlike reflect-metadata, in core-js it can be used without global namespace pollution and can be injected granularly.

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It's time to think about the Metadata Reflection API future in the next major release, here I see only 2 options:

• Drop this legacy out completely
• Think about TS users and leave this legacy to one more major core-js release, add Reflect.decorate for compatibility and better optimize it for granular injection

I'm for the first option - but I'm ready to discuss it.

[zloirock]

@rbuckton

[zloirock]

It seems no one cares, so I'm closing it.