gatsby-node.js

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

exports.createPages = async ({ graphql, actions }) => {
  const { createPage } = actions;
  const blogTemplate = path.resolve(`./src/templates/Blogpost.js`); //template for individual blog posts
  const blogPosts = path.resolve(`./src/templates/blog-post-list.js`); //template for url/blog page
  const result = await graphql(`
    {
      allMdx(sort: { fields: [frontmatter___date], order: DESC }) {
        edges {
          node {
            body
            id
            frontmatter {
              title
            }
            fields {
              slug
            }
          }
        }
      }
    }
  `);

  const posts = result.data.allMdx.edges;
  if (posts.length > 0) {
    posts.forEach((post, index) => {
      const previous = index === 0 ? null : posts[index - 1].node.id;
      const next = index === posts.length - 1 ? null : posts[index + 1].node.id;
      createPage({
        path: `/updates${post.node.fields.slug}`,
        component: blogTemplate,
        context: {
          id: post.node.id,
          previous,
          next,
        },
      });
    });
  }

  const postsPerPage = 4;
  const numPages = Math.ceil(posts.length / postsPerPage);

  Array.from({ length: numPages }).forEach((_, i) => {
    createPage({
      path: i === 0 ? `/updates` : `/updates/${i + 1}`,
      component: blogPosts,
      context: {
        limit: postsPerPage,
        skip: i * postsPerPage,
        numPages,
        currentPage: i + 1,
      },
    });
  });
};

// The following address using slug with MDX 2 and v4 of the plugin
// https://paulie.dev/posts/2022/09/mdx-2-breaking-changes-and-gatsby-plugin-mdx-v4-slug/

exports.onCreateNode = ({ node, getNode, actions: { createNodeField } }) => {
  if (node.internal.type === 'Mdx') {
    createNodeField({
      node,
      name: 'slug',
      value: createFilePath({ node, getNode }),
    });
  }
};

exports.onCreateNode = ({ node, getNode, actions }) => {
  const { createNodeField } = actions;
  if (node.internal.type === `Mdx`) {
    const value = createFilePath({ node, getNode });
    createNodeField({
      name: `slug`,
      value,
      node,
    });
  }
};

//I like turtles