initial gatsby node without createPages

gatsby-node.js

require("dotenv").config();
/**
 * Implement Gatsby's Node APIs in this file.
 *
 * See: https://www.gatsbyjs.org/docs/node-apis/
 */

exports.onCreatePage = ({ page, actions }) => {
  const { createPage, deletePage } = actions

  deletePage(page)
  createPage({
    ...page,
    context: {
      writeKey: `${process.env.COSMIC_WRITE_KEY}`,
      readKey: `${process.env.COSMIC_READ_KEY}`,
      cosmicBucket: `${process.env.COSMIC_BUCKET}`
    }
  })
}