yarn-workspace-lerna.4.next.config.js

const path = require("path");

module.exports = {
  webpack: (config, { defaultLoaders }) => {
      config.resolve.modules.push(path.join(__dirname, "../../packages/"));
      const resolvedBaseUrl = path.resolve(config.context, "../../packages/");
    
      config.module.rules = [
        ...config.module.rules,
        {
          test: /\.(tsx|ts|js|mjs|jsx)$/,
          include: [resolvedBaseUrl],
          use: defaultLoaders.babel,
          exclude: excludePath => {
            return /node_modules/.test(excludePath);
          }
        }
      ];
      
      return config;
    }
  }
}