gatsby-node.js

const path = require('path');

exports.createPages = ({ actions: { createPage } }) => {
  const template = path.resolve('./src/templates/page.jsx');
  const pages = [
    {
      title: 'Homepage',
      slug: '/'
    },

    {
      title: 'Blog',
      slug: 'blog'
    },
    {
      title: 'Blog Item 1',
      slug: 'blog/item-1'
    },
    {
      title: 'Blog Item 2',
      slug: 'blog/item-2'
    },

    {
      title: 'News',
      slug: 'news'
    },
    {
      title: 'News Item 1',
      slug: 'news/item-1'
    },
    {
      title: 'News Item 2',
      slug: 'news/item-2'
    },

    {
      title: 'Contact',
      slug: 'contact'
    }
  ];

  pages.forEach(page => {
    createPage({
      path: page.slug,
      component: template,
      context: { title: page.title }
    });
  });
}