gatsby-plugin-mdx throws on empty line in JSX block

[rakannimer]

Description

When I add a an empty line in a function in a JSX block of an MDX file gatsby-plugin-mdx/loaders/mdx-loader.js throws :

SyntaxError: unknown: Adjacent JSX elements must be wrapped in an enclosing tag. Did you want a JSX fragment <>...</>?

Steps to reproduce

You can either clone this repo : https://github.com/rakannimer/gastby-plugin-mdx-issue-repro

or

gatsby new mdx-gatsby https://github.com/ChristopherBiscardi/gatsby-starter-mdx-basic
cd mdx-gatsby

2. In src/pages/index.mdx add :

import { useState } from "react";

<div>
  <h2>count </h2>
  {() => {
    const [count, setCount] = useState(0);

    return <div onClick={() => setCount(count + 1)}>Some message {count}</div>;

}}

</div>

3. npm start

Expected result

It should allow for empty lines in jsx code blocks.

Actual result

It threw an error.

Environment

System:
OS: macOS 10.14.5
CPU: (8) x64 Intel(R) Core(TM) i7-4870HQ CPU @ 2.50GHz
Shell: 3.2.57 - /bin/bash
Binaries:
Node: 10.16.0 - /var/folders/jn/3z685bls0mv64x4q1vjrzgy40000gn/T/yarn--1569592481666-0.7159453631127595/node
Yarn: 1.17.3 - /var/folders/jn/3z685bls0mv64x4q1vjrzgy40000gn/T/yarn--1569592481666-0.7159453631127595/yarn
npm: 6.9.0 - ~/.nvm/versions/node/v10.16.0/bin/npm
Languages:
Python: 2.7.10 - /usr/bin/python
Browsers:
Chrome: 77.0.3865.90
Firefox: 67.0.4
Safari: 12.1.1
npmPackages:
gatsby: ^2.13.50 => 2.13.50
gatsby-image: ^2.2.8 => 2.2.8
gatsby-plugin-manifest: ^2.2.4 => 2.2.4
gatsby-plugin-mdx: ^1.0.46 => 1.0.46
gatsby-plugin-offline: ^2.2.4 => 2.2.4
gatsby-plugin-react-helmet: ^3.1.3 => 3.1.3
gatsby-plugin-sharp: ^2.2.9 => 2.2.9
gatsby-source-filesystem: ^2.1.8 => 2.1.8
gatsby-transformer-sharp: ^2.2.5 => 2.2.5

[kgabryje]

Hey, can I take this one?

[samjt]

This is actually an issue with mdx-js
mdx-js/mdx#767

[csywweb]

i have a same question

[samjt]

This issue isn’t resolved, the problem still exists up the dependency tree

[johno]

I'm going to go ahead and close this since it needs to be addressed upstream. There's nothing actionable on Gatsby or gatsby-plugin-mdx's end.