How to exclude specified files when packing by rollup

how rollup excludes specified files when packaging, or packages into two files.

now the project needs to output two files after packaging, one logical file and one configuration file (config)

utils.js
config.js

however, it will not be configured.

is there any way to achieve this?

Dec.21,2021

{
   external: id => /config.js/.test(id)
}

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