Port Relay Babel plugin to SWC

[timneutkens]

@hanford has done a bunch of research into porting babel-plugin-relay. It comes down to this fairly simple transform: https://gist.github.com/hanford/10401629eb7d82d47b275f59356d86f5 so I think we can port it to SWC relatively easily without having to implement a GraphQL parser.

Message from @hanford:

All babel-plugin-relay does, is look for `graphql``` tagged template literals, performs a regex to extract the name of the operation and then generates appends ImportDefaultSpecifier with that name.

• Before babel-plugin-relay running:

  function MyQueryRenderer () {
    return (
      <QueryRenderer
      	query={graphql`
  				query SearchUserQuery {
  					findUser {
  						name
  					}
  				}
  		`}
  	/>
    )
  }

• After babel-plugin-relay runs:

  import graphql__a6767a3b from "dazzle-types/SearchUserQuery.graphql";
  
  function MyQueryRenderer () {
    return (
        <QueryRenderer
            query={graphql__a6767a3b}
        />
    );
  }

In addition to the babel plugin I created, I also have a JSCodeshift that I've been running on our frontend to then allow me to begin playing around with SWC.

The source for the JSCodeshift is below:

https://gist.github.com/hanford/003f07533f7bfc8af7fc90a838f0e963

[AndrewIngram]

FYI the links above point to notion pages rather than gists

[AndrewIngram]

Something to bare in mind is that because the transforms generate an import declaration, any such plugin would need to be able to read a project's Relay configuration to determine where the artifactDirectory is. The default is a __generated__ directory that's a sibling to whatever module is being transformed, but it could also be a globally configured location.

[rrdelaney]

In JS-world artifactDirectory is pretty easy to get via the relay-config package:

> require('relay-config').loadConfig().artifactDirectory
'src/queries/__generated__'`

[tony]

The next stable release of relay v13 will be in rust (their checklist, compiler/)

In the next major Relay Release (v13) the new rust version of the compiler will be the only version.
- 2 weeks ago in Bye, JS Compiler, we love you!@4467ae8

Can relay being in rust benefit this effort in any way?

[timneutkens]

Can relay being in rust benefit this effort in any way?

As far as I'm aware the answer is no because the compiler would already be run next to having the transform.

[wongmjane]

fyi: relay-config has been removed

facebook/relay#3677

[aalises]

🤸‍♂️ What's the status on this? waiting for it to finally move to SWC.

[tbezman]

@aalises and other folks in this thread. I tried adding support for Relay in #33240 . Can y'all check it out and give feedback?