pokemon.trade/config/webpack/environment.js

const {environment} = require('@rails/webpacker');

module: {
  rules: [
    {
      test: /\.js(\.erb)?$/,
      exclude: /node_modules/,
      loader: 'babel-loader',
      options: {
        presets: [['env', {modules: false}]],
      },
    },
  ];
}

environment.loaders.get('sass').use.splice(-1, 0, {
  loader: 'resolve-url-loader',
  options: {
    attempts: 1,
  },
});

module.exports = environment;