gatsby-node.js

const defines = require('./babel-defines')

exports.onCreateWebpackConfig = ({actions, plugins, getConfig}) => {
  const config = getConfig()
  // Add our `__DEV__` and `process.env.NODE_ENV` defines
  config.plugins.push(plugins.define(defines[process.env.NODE_ENV || 'development']))

  // Polyfill `path` and stub `fs` for use in the browser
  // https://www.gatsbyjs.com/docs/reference/release-notes/migrating-from-v2-to-v3/#webpack-5-node-configuration-changed-nodefs-nodepath-
  config.resolve = {
    ...config.resolve,
    alias: {
      ...config.resolve.alias,
      path: require.resolve('path-browserify'),
    },
    fallback: {
      ...config.resolve.fallback,
      fs: false,
    },
  }

  actions.replaceWebpackConfig(config)
}