Build fails when a service has a nodejs dependency in a sub-folder

[paultranvan]

Suppose we have a service in targets/services/service.js, that requires a file in targets/services/subdir/file.js, that itself requires a nodejs dependency, e.g. fs. When trying to build the service with cozy-scripts through yarn watch, an error will throw: Module not found: Error: Can't resolve 'fs'. This is because cozy-scripts will only consider js files in targets/services/ but not in subfolder: https://github.com/cozy/create-cozy-app/blob/4b790b81f11c5485a23ad02f7be0bc3dd5219776/packages/cozy-scripts/config/webpack.config.services.js#L15-L19

Hence, any file in subdir/ requiring a nodejs primitive will fail.

A workaround would be to recursively find any .js file in targets/services/service.js, but I'm not sure this is the correct approach, as any file will be a new entry: https://github.com/cozy/create-cozy-app/blob/4b790b81f11c5485a23ad02f7be0bc3dd5219776/packages/cozy-scripts/config/webpack.config.services.js#L33

We met this issue with @JulienMirval when trying to use cozy-konnector-libs in a service: https://github.com/JulienMirval/dissec_cozy/blob/ee206472c49c723af630e1d740c1e0384dc73b64/src/targets/services/helpers/model.js#L2

Any thoughts?