gatsby-node.js

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

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

  const blogPost = path.resolve(`./src/templates/blog-post.js`)
  const cheatPost = path.resolve(`./src/templates/cheat-post.js`)
  const infographicPost = path.resolve(`./src/templates/infographic-post.js`)
  const revealPost = path.resolve(`./src/templates/reveal-post.js`)
  const tagTemplate = path.resolve(`./src/templates/tag.js`)

  return graphql(
    `
      {
        blogsGroup: allMdx(
          sort: { fields: [frontmatter___date], order: DESC }
          limit: 1000
          filter: {
            frontmatter: { cheat: { ne: true }, infographic: { ne: true } }
          }
        ) {
          edges {
            node {
              id
              fields {
                slug
              }
              frontmatter {
                title
              }
              body
            }
          }
        }
        cheatsGroup: allMdx(
          sort: { fields: [frontmatter___date], order: DESC }
          limit: 1000
          filter: { frontmatter: { cheat: { in: true } } }
        ) {
          edges {
            node {
              id
              fields {
                slug
              }
              frontmatter {
                title
              }
              body
            }
          }
        }
        infographicsGroup: allMdx(
          sort: { fields: [frontmatter___date], order: DESC }
          limit: 1000
          filter: { frontmatter: { infographic: { in: true } } }
        ) {
          edges {
            node {
              id
              fields {
                slug
              }
              frontmatter {
                title
              }
              body
            }
          }
        }
        revealsGroup: allMarkdownRemark(
          filter: { frontmatter: { reveal: { in: true } } }
        ) {
          edges {
            node {
              id
              fields {
                slug
              }
              frontmatter {
                reveal
              }
            }
          }
        }
        tagsGroup: allMdx(limit: 2000) {
          group(field: frontmatter___tags) {
            fieldValue
          }
        }
      }
    `
  ).then(result => {
    if (result.errors) {
      throw result.errors
    }

    // Create blog posts pages.
    const posts = result.data.blogsGroup.edges
    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,
        },
      })
    })

    // create cheat post pages
    const cheats = result.data.cheatsGroup.edges
    cheats.forEach((cheat, index) => {
      createPage({
        path: cheat.node.fields.slug,
        component: cheatPost,
        context: {
          slug: cheat.node.fields.slug,
        },
      })
    })

    // create infographics pages
    const infographics = result.data.infographicsGroup.edges
    infographics.forEach((igraphic, index) => {
      createPage({
        path: igraphic.node.fields.slug,
        component: infographicPost,
        context: {
          slug: igraphic.node.fields.slug,
        },
      })
    })

    // create reveal slide page
    const reveals = result.data.revealsGroup.edges
    reveals.forEach(reveal => {
      createPage({
        path: reveal.node.fields.slug,
        component: revealPost,
        context: {
          slug: reveal.node.fields.slug,
        },
      })
    })

    // create tag pages
    const tags = result.data.tagsGroup.group
    tags.forEach(tag => {
      createPage({
        path: `/tags/${tag.fieldValue}/`,
        component: tagTemplate,
        context: {
          tag: tag.fieldValue,
        },
      })
    })
  })
}

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

  if (node.internal.type === `Mdx` || node.internal.type === `MarkdownRemark`) {
    const value = createFilePath({ node, getNode })
    createNodeField({
      name: `slug`,
      node,
      value,
    })
  }
}

// exports.onCreateWebpackConfig = ({ actions }) => {
//   actions.setWebpackConfig({
//     node: { fs: 'empty' },
//   })
// }