gatsby-node.js

const { kebabCase } = require("lodash");

const createTagPages = require("./gatsby-actions/createTagPages");
const createCategoryPages = require("./gatsby-actions/createCategoryPages");
const createArchivePages = require("./gatsby-actions/createArchivePages");
const createPostPages = require("./gatsby-actions/createPostPages");
const createPaginatedPages = require("gatsby-paginate");
const filterStr =
  process.env.NODE_ENV === "production"
    ? "filter: { frontmatter: { draft: { ne: true } } }"
    : "";
exports.createPages = ({ graphql, actions }) => {
  const { createPage } = actions;
  return new Promise((resolve, reject) => {
    resolve(
      graphql(`
        {
          posts: allMarkdownRemark(
            sort: { frontmatter: { date: DESC } }
            ${filterStr}
          ) {
            totalCount
            edges {
              node {
                wordCount{
                  words
                }
                timeToRead
                fields {
                  slug
                }
                html
                frontmatter {
                  slug
                  title
                  date
                  category
                  tags
                  cover
                }
                tableOfContents
                excerpt(pruneLength: 150)
              }
            }
          }
        }
      `).then((result) => {
        if (result.errors) {
          console.log(result.errors);
          reject(result.errors);
        }
        const posts = result.data.posts.edges;

        createPostPages(createPage, posts);
        createArchivePages(createPage, createPaginatedPages, posts);
        createTagPages(createPage, createPaginatedPages, posts);
        createCategoryPages(createPage, createPaginatedPages, posts);
        resolve();
      })
    );
  });
};

exports.onCreateNode = ({ node, actions }) => {
  const { createNodeField } = actions;
  if (node.internal.type === "MarkdownRemark") {
    let slug = "";
    const fileName = node.fileAbsolutePath.split("/").pop();
    const title = fileName.substring(0, fileName.length - 3);
    if (
      Object.prototype.hasOwnProperty.call(node, "frontmatter") &&
      Object.prototype.hasOwnProperty.call(node.frontmatter, "slug")
    ) {
      slug = `/posts/${kebabCase(node.frontmatter.slug)}`;
      node.frontmatter.slug = slug;
    }

    node.frontmatter.title = title;
    node.frontmatter.date = new Date(
      node.frontmatter.date.replace(/-/g, "/")
    ).toISOString();
    createNodeField({ node, name: "slug", value: slug });
  }
};