gatsby-node.js

const path = require('path')

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

 if (node.internal.type === 'Mdx') {
 const parent = getNode(node.parent)

 if (parent.internal.type === 'File') {
 createNodeField({
 name: 'sourceName',
 node,
 value: parent.sourceInstanceName,
 })
 }
 }
}

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

 const blogPosts = await graphql(`
 {
 allMdx(
 filter: { fields: { sourceName: { eq: "blog" } } }
 sort: { fields: frontmatter___date, order: DESC }
 limit: 1000
 ) {
 nodes {
 slug
 }
 }
 }
 `)

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

 const posts = blogPosts.data.allMdx.nodes
 const postsPerPage = 6
 const numPages = Math.ceil(posts.length / postsPerPage)
 Array.from({ length: numPages }).forEach((_, i) => {
 createPage({
 path: i === 0 ? `/blog` : `/blog/${i + 1}`,
 component: path.resolve('./src/templates/blog-list-template.tsx'),
 context: {
 limit: postsPerPage,
 skip: i * postsPerPage,
 numPages,
 currentPage: i + 1,
 },
 })
 })
}