gatsby-node.js

const path = require(`path`)
const config = require('./gatsby-config')

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

  const blogPostTemplate = path.resolve(`src/templates/blogTemplate.js`)
  const pageTemplate = path.resolve(`src/templates/pageTemplate.js`)

  const result = await graphql(`
    {
      allMarkdownRemark(
        sort: { order: DESC, fields: [frontmatter___date] }
        limit: 1000
      ) {
        edges {
          node {
            fileAbsolutePath
            frontmatter {
              path
            }
          }
        }
      }
    }
  `)

  // Handle errors
  if (result.errors) {
    reporter.panicOnBuild(`Error while running GraphQL query.`)
    return
  }

  result.data.allMarkdownRemark.edges.forEach(({ node }) => {
    createPage({
      path: node.frontmatter.path,
      component: node.fileAbsolutePath.match(/\/md-pages\//i)
        ? pageTemplate
        : blogPostTemplate,
      context: {
        permalink: `${config.siteMetadata.websiteUrl}${node.frontmatter.path}`
      }
    })
  })
}