CORS support

[carcinocron]

No description provided.

[m0ksem]

@pi0. Do you want to work on it? I could make a PR for CORS support.

[NozomuIkuta]

For your reference, I'm creating h3-native CORS event handler, whose APIs are mostly same as Express CORS middleware.

README is not yet written, but I believe the code is so simple that you can understand what API looks like.

I've implemented basic features and unit tests, and now I need a kind of e2e tests to test CORS works as expected.
Any advice or feedback is welcome.

[NozomuIkuta]

For your reference, I'm creating h3-native CORS event handler, whose APIs are mostly same as Express CORS middleware.

I published it to npm with additional unit tests and README.

https://www.npmjs.com/package/@nozomuikuta/h3-cors

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By the way, this is my first experience of using unjs/template.
I found some points to improve, so I will create issues and submit PRs later.

[NozomuIkuta]

@pi0
By the way, may I add my package above to Add-on section in README?

[NozomuIkuta]

h3-cors package provides enough functionality, so I believe it's fine to close this issue for now.

📝 This issue might need to be reopened according to organization members' decision on #259 (exporting middlewares from main repository).

[pi0]

I think we shall still add cors utility to the h3 main utils. NozomuIkuta/h3-cors#10