Usually you setup a transpiler to target both. For example, my packages are bundled with rollup towards both cjs & esm: https://github.com/arcanis/clipanion/bl

Usually you setup a transpiler to target both. For example, my packages are bundled with rollup towards both cjs & esm: https://github.com/arcanis/clipanion/blob/master/rollup.config.js#L6-L17 https://github.com/arcanis/clipanion/blob/master/rollup.conf...