Needs documentation for how to use new JSX transform

Summary

React says that Gatsby 2.24.+ supports the new JSX transform (and there’s a merged PR here claiming it is supported) so we don’t need to import * as React from 'react' anymore for React 17. So I started a new Gatsby project (2.26.x). It installed React 16.x, which doesn’t support the new transform. I updated react and react-dom to 17.0.1 and removed the import * as React from 'react' line from src/pages/index.js and now I get a bunch of

101:5   error  'React' must be in scope when using JSX react/react-in-jsx-scope

for that file.

Motivation

It should be documented because React and Gatsby both claim to support this for React 17, but there do not seem to be instructions for how to make this work.

Steps to resolve this issue

Hell if I know. I’ve been trying to get this to work for a couple days now. Once it’s working, I’m going to try to get it working with TypeScript, which I also failed to get working the past day.

[LekoArts]

@Austaras https://www.gatsbyjs.com/docs/reference/config-files/gatsby-config/#jsxruntime

[Austaras]

@kylegoetz Thanks for opening the issue. We’re working on supporting the new jsx transforms. Currently they are not supported unless you create a custom babelrc and mimic what babel-preset-gatsby does.

@wardpeet any progress or roadmap yet?