gatsby-node.js

/**
 * @type {import('gatsby').GatsbyNode['createPages']}
 */
/**
 * Implement Gatsby's Node APIs in this file.
 *
 * See: <https://www.gatsbyjs.com/docs/node-apis/>
 */

// You can delete this file if you're not using it

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

// Setup Import Alias
exports.onCreateWebpackConfig = ({ getConfig, actions }) => {
  const output = getConfig().output || {};

  actions.setWebpackConfig({
    output,
    resolve: {
      alias: {
        components: path.resolve(__dirname, 'src/components'),
        utils: path.resolve(__dirname, 'src/utils'),
        hooks: path.resolve(__dirname, 'src/hooks'),
      },
    },
  });
};

// Generate a Slug Each Post Data
exports.onCreateNode = ({ node, getNode, actions }) => {
  const { createNodeField } = actions;

  if (node.internal.type === `MarkdownRemark`) {
    const slug = createFilePath({ node, getNode, basePath: 'contents' });

    createNodeField({ node, name: 'slug', value: slug });
  }
};

// Ensure optional fields exist in GraphQL schema
exports.createSchemaCustomization = ({ actions }) => {
  const { createTypes } = actions;

  createTypes(`
    type MarkdownRemarkFields {
      slug: String!
    }

    type MarkdownRemarkFrontmatter {
      thumbnail: File @fileByRelativePath
    }

    type MarkdownRemark implements Node {
      fields: MarkdownRemarkFields
    }
  `);
};

// Generate Post Page Through Markdown Data
exports.createPages = async ({ actions, graphql, reporter }) => {
  const { createPage } = actions;

  // Get All Markdown File For Paging
  const queryAllMarkdownData = await graphql(`
    {
      allMarkdownRemark(sort: [{ frontmatter: { date: DESC } }, { frontmatter: { title: ASC } }]) {
        edges {
          node {
            fields {
              slug
            }
          }
        }
      }
    }
  `);

  // Handling GraphQL Query Error
  if (queryAllMarkdownData.errors) {
    reporter.panicOnBuild(`Error while running query`);
    return;
  }

  // Import Post Template Component
  const PostTemplateComponent = path.resolve(__dirname, 'src/templates/post_template.tsx');

  // Page Generating Function
  const generatePostPage = ({
    node: {
      fields: { slug },
    },
  }) => {
    const pageOptions = {
      path: slug,
      component: PostTemplateComponent,
      context: { slug },
    };

    createPage(pageOptions);
  };

  // Generate Post Page And Passing Slug Props for Query
  queryAllMarkdownData.data.allMarkdownRemark.edges.forEach(generatePostPage);
};