Adds support for rendering MDX as a Server Component.
The main reason a MDX file couldn't be rendered as a Server Component is
that `@mdx-js/react` has a legacy/deprecated context setup in the file.
Because of calling `React.createContext` the MDX file couldn't be a
Server Component.
I've added support for a special file `mdx-components.tsx` (or `.js`) at
the root of the project (can be `src` dir too).
By using mdx-components you don't need a global context provider which
in turn makes MDX compatible to be rendered as a Server Component.
Note: this changes `@next/mdx` to add support for that file so it has to
be landed first before the example works.
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## Bug
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have a helpful link attached, see
[`contributing.md`](https://github.com/vercel/next.js/blob/canary/contributing.md)
## Feature
- [ ] Implements an existing feature request or RFC. Make sure the
feature request has been accepted for implementation before opening a
PR.
- [ ] Related issues linked using `fixes #number`
- [ ]
[e2e](https://github.com/vercel/next.js/blob/canary/contributing/core/testing.md#writing-tests-for-nextjs)
tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have a helpful link attached, see
[`contributing.md`](https://github.com/vercel/next.js/blob/canary/contributing.md)
## Documentation / Examples
- [ ] Make sure the linting passes by running `pnpm build && pnpm lint`
- [ ] The "examples guidelines" are followed from [our contributing
doc](https://github.com/vercel/next.js/blob/canary/contributing/examples/adding-examples.md)
Co-authored-by: JJ Kasper <jj@jjsweb.site>
