text: const _ = require("lodash");
  const path = require("path");
  const { createFilePath } = require("gatsby-source-filesystem");
  const { fmImagesToRelative } = require("gatsby-remark-relative-images");
  
  exports.createPages = ({ actions, graphql }) => {
    const { createPage } = actions;
    const blogPost = path.resolve(`./src/templates/blog-post.js`);
  
    return graphql(`
      {
        allMarkdownRemark(limit: 1000) {
          edges {
            node {
              id
              fields {
                slug
              }
              frontmatter {
                tags
                templateKey
              }
            }
          }
        }
      }
    `).then(result => {
      if (result.errors) {
        result.errors.forEach(e => console.error(e.toString()));
        return Promise.reject(result.errors);
      }
  
      const posts = result.data.allMarkdownRemark.edges;
  
      posts.forEach(edge => {
        const id = edge.node.id;
        createPage({
          path: edge.node.fields.slug,
          tags: edge.node.frontmatter.tags,
          component: blogPost,
          // additional data can be passed via context
          context: {
            id
          }
        });
      });
  
      // Create blog post list pages
      const postsPerPage = 12;
      const numPages = Math.ceil(posts.length / postsPerPage);
  
      Array.from({ length: numPages }).forEach((_, i) => {
        createPage({
          path: i === 0 ? `/` : `/${i + 1}`,
          component: path.resolve("./src/templates/blog-list.js"),
          context: {
            limit: postsPerPage,
            skip: i * postsPerPage,
            numPages,
            currentPage: i + 1
          }
        });
      });
  
      // Tag pages:
      let tags = [];
      // Iterate through each post, putting all found tags into `tags`
      posts.forEach(edge => {
        if (_.get(edge, `node.frontmatter.tags`)) {
          tags = tags.concat(edge.node.frontmatter.tags);
        }
      });
      // Eliminate duplicate tags
      tags = _.uniq(tags);
  
      // Make tag pages
      tags.forEach(tag => {
        const tagPath = `/tags/${_.kebabCase(tag)}/`;
  
        createPage({
          path: tagPath,
          component: path.resolve(`src/templates/tags.js`),
          context: {
            tag
          }
        });
      });
    });
  };
  
  exports.onCreateNode = ({ node, actions, getNode }) => {
    const { createNodeField } = actions;
    fmImagesToRelative(node); // convert image paths for gatsby images
  
    if (node.internal.type === `MarkdownRemark`) {
      const value = createFilePath({ node, getNode });
      createNodeField({
        name: `slug`,
        node,
        value
      });
    }
  };
  