(core) - Add built-in gql tag function

[kitten]

Summary

No RFC, since this is a rather small change that naturally emerged after #1186

We can merge the functionality of graphql-tag into a leaner function in @urql/core. Our implementation does not check fragment names globally, so that it works well with @urql/exchange-graphcache but mostly checks them in the document that's currently generated.

The output is still compatible with graphql-tag and works similarly. There's potential for more optimisations, but the most important optimisation is that the function reuses the key-cache of request.ts in the same file.

The size increase is negligible and could be gained back with more refactors potentially (0.1kB gzip)

[changeset-bot]

🦋 Changeset detected

Latest commit: 4b18626

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 5 packages

Name	Type
@urql/core	Minor
@urql/preact	Patch
urql	Patch
@urql/svelte	Patch
@urql/vue	Patch

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[JoviDeCroock]

This is superb

[zachasme]

We tried replacing graphql-tag with this built-in tag, but as far as I can tell this doesn't do fragment de-duplication, which we rely on.

Do you still recommend using graphql-tag when de-duplication is needed, or is there another approach using the built-in tag?

[kitten]

@zachasme Just so I don't miss the point here; I suppose we may have forgotten to handle duplicate identical fragments? I'll look into that! That's a good point 👍

Edit: #1225 should address this concern

[zachasme]

Yes exactly, duplicate identical fragments. I was wondering if it was intentionally left out :)

[kitten]

@zachasme well, I hope that with the patch this is going to work just fine now ✌️ I hope that didn't waste any time on your part and will work as expected

[zachasme]

Wow that was fast, and it appears to be working--thanks a bunch, @kitten! 👍

No time wasted, I only did a quick search+replace on our develop branch last week to try it out, and wrote the comment to figure out what was happening.