gatsby-node.js

/**
 * Implement Gatsby's Node APIs in this file.
 *
 * See: https://www.gatsbyjs.org/docs/node-apis/
 */
const path = require('path')
const { createFilePath } = require('gatsby-source-filesystem')

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

  return new Promise(resolve => {
    createPage({
      path: '/',
      matchPath: '/:path',
      component: path.resolve('./src/app.js'),
    })

    graphql(`
      {
        allMarkdownRemark {
          edges {
            node {
              fields {
                slug
              }
            }
          }
        }
      }
    `).then(result => {
      result.data.allMarkdownRemark.edges.forEach(({ node }) => {
        createPage({
          path: node.fields.slug,
          component: path.resolve('./src/templates/blog.js'),
        })
      })
      resolve()
    })
  })
}

exports.onCreateNode = ({ node, getNode, actions }) => {
  const { createNodeField } = actions
  if (node.internal.type === 'MarkdownRemark') {
    const slug = createFilePath({
      node,
      getNode,
      basePath: 'pages',
      trailingSlash: false,
    })

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