How i got this blog site up with Gatsby

I initially wanted to serve Markdown files, but then made the decision in favor of MDX because of it's capability to render Markdown mixed with JSX.

npx gatsby new
npm run develop # start dev server http://localhost:8000
npm run build # build production site
npm run serve # serve production site you built, http://localhost:9000

npx gatsby help # show available commands
npx gatsby new help # show help for a specific command

Rendering Markdown files

We need a source plugin to source files from a folder, and then we need a transformer plugin to transform markdown to something Gatsby can query via GraphQL.

npm i gatsby-source-filesystem gatsby-transformer-remark


I always had this issue where i couldn't use CSS classes in Makrdown, and if i did add any HTML, any markdown wouldn't render inside that HTML block. MDX fixes that. I can write in the Markdown that i am familiar with, and add all the jazz with JSX as well.

Using it with Gatsby is pretty easy.

npm i gatsby-plugin-mdx @mdx-js/mdx@latest @mdx-js/react@latest gatsby-plugin-page-creator

By default, it'll pick any files inside the src/pages directory. If you want it to pick up from other directories and automatically build, you need the gatsby-plugin-page-creator plugin, and the directory should already be sourced with gatsby-source-filesystem. Here's a sample config where i am using src/posts as my directory for blog posts

plugins: [
    resolve: `gatsby-source-filesystem`,
    options: {
      name: `posts`,
      path: `${__dirname}/src/posts/`,
      ignore: [`**/\.*`], // ignore files starting with a dot
    resolve: 'gatsby-plugin-page-creator',
    options: {
      path: `${__dirname}/src/posts`,


# install Sass plugins
npm install --save node-sass gatsby-plugin-sass

add gatsby-plugin-sass to plugins array in gatsby-config.js

Convert the .css files to .scss and you're good.


React hooks error

  1. You might have mismatching versions of React and the renderer (such as React DOM)
  2. You might be breaking the Rules of Hooks
  3. You might have more than one copy of React in the same app
  See for tips about how to debug and fix this problem.

This was probably caused by Gatsby starter kit using outdated versions.. if you get this random error about React hooks, do this

  • delete node_modules and package-lock.json
  • npm install

and then

npm uninstall react react-dom gatsby
npm install react react-dom gatsby

Build failed because path doesn't exist

12:01:43 PM: The path passed to gatsby-source-filesystem does not exist on your file system:
12:01:43 PM: /opt/build/repo/src/data
12:01:43 PM: Please pick a path to an existing directory.
12:01:43 PM: See docs here -

This was fixed by commenting out the code sourcing src/data (also removed trailing slashes for good measure). To be clear, the directory existed, it just didn't have any files, i.e. empty directory.

I had added it during configuration because i thought i might need it later.



Please note that this site and the posts on it are, and will always be, a work in progress. If i waited for perfection, i’d never get anything done.