gatsby-node.js

/**
 * Implement Gatsby's Node APIs in this file.
 *
 * See: https://www.gatsbyjs.org/docs/node-apis/
 */
const path = require('path')
const _ = require('lodash')
const fs = require("fs-extra")

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

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

// exports.onPostBuild = () => {
//   console.log("Copying locales")
//   fs.copySync(
//     path.join(__dirname, "/src/locales"),
//     path.join(__dirname, "/public/locales")
//   )
// }

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

  const blogPostTemplate = path.resolve(`src/templates/blog-post.js`)
  const tagTemplate = path.resolve(`src/templates/tags.js`)
  const result = await graphql(
    `
      {
        postsRemark: allMarkdownRemark(
          sort: { order: DESC, fields: [frontmatter___date] }
          limit: 2000
        ) {
          edges {
            node {
              excerpt(pruneLength: 250)
              html
              id
              frontmatter {
                date
                path
                title
                featuredImage
                isFeatured
                tags
                canonicalUrl
              }
            }
          }
        }
        tagsGroup: allMarkdownRemark(limit: 2000) {
          group(field: frontmatter___tags) {
            fieldValue
          }
        }
      }
    `
  )

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

  const posts = result.data.postsRemark.edges

  // Create post detail pages
  posts.forEach(({ node }) => {
    createPage({
      path: node.frontmatter.path,
      component: blogPostTemplate,
    })
  })

  // Extract tag data from query
  const tags = result.data.tagsGroup.group

  // Make tag pages
  tags.forEach(tag => {
    createPage({
      path: `/tags/${_.kebabCase(tag.fieldValue)}/`,
      component: tagTemplate,
      context: {
        tag: tag.fieldValue,
      },
    })
  })
}