gatsby-node.js

const path = require(`path`)
const { createFilePath } = require(`gatsby-source-filesystem`)

exports.createPages = async ({ graphql, actions }) => {
  const { createPage } = actions

  const blogPost = path.resolve(`./src/templates/blog-post.js`)
  const result = await graphql(
    `
      {
        allMdx(
          sort: { fields: [frontmatter___date], order: DESC }
          limit: 1000
        ) {
          edges {
            node {
              fields {
                slug
              }
              frontmatter {
                title
                date
              }
            }
          }
        }
      }
    `
  )

  if (result.errors) {
    throw result.errors
  }

  // Get mdx posts
  const posts = result.data.allMdx.edges

  // Iterate posts and create pages
  posts.forEach((post, index) => {
    const previous = index === posts.length - 1 ? null : posts[index + 1].node
    const next = index === 0 ? null : posts[index - 1].node

    createPage({
      path: post.node.fields.slug,
      component: blogPost,
      context: {
        slug: post.node.fields.slug,
        previous,
        next,
      },
    })
  })
}

exports.onCreateNode = ({ node, actions, getNode }) => {
  const { createNodeField } = actions

  if (node.internal.type === "Mdx") {
    const value = createFilePath({ node, getNode })
    createNodeField({
      // Name of the field you are adding
      name: "slug",
      // Individual MDX node
      node,
      // Generated value based on filepath with "blog" prefix. you
      // don't need a separating "/" before the value because
      // createFilePath returns a path with the leading "/".
      value: `/blog${value}`,
    })
  }
}

exports.onCreateWebpackConfig = ({ actions, loaders, getConfig }) => {
  const config = getConfig()
  config.node = {
    fs: 'empty'
  }
}