gatsby-node.js

/**
 * Implement Gatsby's Node APIs in this file.
 *
 * See: https://www.gatsbyjs.com/docs/node-apis/
 */

// You can delete this file if you're not using it

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

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

  if (node.internal.type === "Mdx") {
    const slug = createFilePath({ node, getNode })

    createNodeField({
      node,
      name: "slug",
      value: slug,
    })
  }
}

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

  // **Note:** The graphql function call returns a Promise
  // see: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise for more info
  const result = await graphql(`
    query {
      allMdx {
        edges {
          node {
            id
            frontmatter {
              title
            }
            body
            fields {
              slug
            }
          }
        }
      }
    }
  `)

  if (result.errors) {
    reporter.panicOnBuild('🚨  ERROR: Loading "createPages" query')
  }

  result.data.allMdx.edges.forEach(({ node }) => {
    createPage({
      path: node.fields.slug,
      component: path.resolve(`./src/templates/content-page.js`),
      // Data passed to context is available
      // in page queries as GraphQL variables.
      context: {
        id: node.id,
        frontmatter: node.frontmatter,
        body: node.body,
      },
    })
  })
}