module.exports = ({ config }) => {
  // Transpile Gatsby module because Gatsby includes un-transpiled ES6 code.
  config.module.rules[0].exclude = [/node_modules\/(?!(gatsby)\/)/]

  // use installed babel-loader which is v8.0-beta (which is meant to work with @babel/core@7)
  config.module.rules[0].use[0].loader = require.resolve("babel-loader")

  // use @babel/preset-react for JSX and env (instead of staged presets)
  config.module.rules[0].use[0].options.presets = [
    require.resolve("@babel/preset-react"),
    require.resolve("@babel/preset-env"),
  ]

  config.module.rules[0].use[0].options.plugins = [
    // use @babel/plugin-proposal-class-properties for class arrow functions
    require.resolve("@babel/plugin-proposal-class-properties"),
    // use babel-plugin-remove-graphql-queries to remove static queries from components when rendering in storybook
    require.resolve("babel-plugin-remove-graphql-queries"),
  ]

  // Prefer Gatsby ES6 entrypoint (module) over commonjs (main) entrypoint
  config.resolve.mainFields = ["browser", "module", "main"]

  config.module.rules.push({
    test: /\.(ts|tsx)$/,
    loader: require.resolve("babel-loader"),
    options: {
      presets: [["react-app", { flow: false, typescript: true }]],
      plugins: [
        require.resolve("@babel/plugin-proposal-class-properties"),
        // use babel-plugin-remove-graphql-queries to remove static queries from components when rendering in storybook
        require.resolve("babel-plugin-remove-graphql-queries"),
      ],
    },
  })
  config.resolve.extensions.push(".ts", ".tsx")

  return config
}