esbuild-copy-files.mjs

import fs from 'fs/promises';

const copyFilesPlugin = (options = {}) => ({
  name: 'copy-files',
  setup(build) {
    build.onEnd(async () => {
      await Promise.all(
        Object.entries(options).map(([_, target]) => fs.writeFile(target, '')),
      );

      await Promise.all(
        Object.entries(options).map(async ([source, target]) =>
          fs.cp(source, target),
        ),
      );
    });
  },
});

export default copyFilesPlugin;