I'm in the process of implementing rollup into my mono repo library for better bundling.

Issue

Since the library is a mono repo, I want to reuse build configurations for the individual packages. I've tried to do so by outsourcing methods that return specific build configurations(e.g. createCommonJsConfig(), createESMConfig()) into a file called rollup.default.config.ts which is located at the root of the mono repo.

These functions are then imported into the rollup.config.js file of each package to create the final rollup configuration.

// rollup.config.js of an individual package

import {
  createCommonJSConfig,
  createDeclarationConfig,
  createESMConfig,
} from '../rollup.config.default';

// https://rollupjs.org/guide/en/#configuration-files
export default function () {
  return [
    createDeclarationConfig(),
    createCommonJSConfig(),
    createESMConfig({ multiFileOutput: true }),
  ];
}

Unfortunately, as soon as I import the rollup.config.default.ts file into a rollup.config.js file of a package, I get this error:

[!] Error: Could not resolve '../rollup.config.default' from rollup.config.js

Question

Does anybody know whether it is possible to somehow modularize a rollup.config.js file to reuse commonly used parts.

• repo: https://github.com/agile-ts/agile
• rollup.default.config.ts: https://github.com/agile-ts/agile/blob/removing-internal/packages/rollup.config.default.ts

Thanks a lot ;D