gatsby-node.js

const path = require('path');

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

// Adiciona o slug para cada post
exports.onCreateNode = ({ node, getNode, actions }) => {
  const { createNodeField } = actions;
  if (node.internal.type === 'MarkdownRemark') {
    // Use `createFilePath` to turn markdown files in our `data/faqs` directory into `/faqs/slug`
    const slug = createFilePath({
      node,
      getNode,
      basePath: 'pages',
    });

    // Creates new query'able field with name of 'slug'
    createNodeField({
      node,
      name: 'slug',
      // Retira a data do inico de cada post
      value: `/${slug.slice(12)}`,
    });
  }
};

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

  return graphql(`
    {
      allMarkdownRemark(sort: { fields: frontmatter___date, order: DESC }) {
        edges {
          node {
            fields {
              slug
            }
            frontmatter {
              background
              category
              description
              title
              date(locale: "pt-br", formatString: "DD [de] MMMM [de] YYYY")
              image
            }
            timeToRead
          }
          next {
            fields {
              slug
            }
            frontmatter {
              title
            }
          }
          previous {
            fields {
              slug
            }
            frontmatter {
              title
            }
          }
        }
      }
    }
  `).then(result => {
    const posts = result.data.allMarkdownRemark.edges;

    posts.forEach(({ node, next, previous }) => {
      createPage({
        path: node.fields.slug,
        component: path.resolve('./src/templates/blog-post.js'),
        context: {
          slug: node.fields.slug,
          previousPost: next,
          nextPost: previous,
        },
      });
    });

    const postsPerPage = 6;
    const numPages = Math.ceil(posts.length / postsPerPage);

    Array.from({ length: numPages }).forEach((_, index) => {
      createPage({
        // se for 0, é a Home, senao, cria a pagina
        path: index === 0 ? '/' : `/page/${index + 1}`,
        component: path.resolve(`./src/templates/blog-list.js`),
        context: {
          limit: postsPerPage,
          skip: index * postsPerPage,
          numPages,
          currentPage: index + 1,
        },
      });
    });
  });
};