react.dev/plugins/gatsby-source-react-error-codes/gatsby-node.js

const request = require('request-promise');

const errorCodesUrl = 'http://raw.githubusercontent.com/facebook/react/master/scripts/error-codes/codes.json';

exports.sourceNodes = async ({ boundActionCreators }) => {
  const { createNode } = boundActionCreators;

  const jsonString = await request(errorCodesUrl);

  createNode({
    id: 'error-codes',
    children: [],
    parent: 'ERRORS',
    internal: {
      type: 'ErrorCodesJson',
      contentDigest: jsonString,
    },
  });
};