I am building a components library which is pre-compiled using Rollup.

My components lib has hundreds of files, at random depths, and I need all files with specific name pattern (*.constants.js) to not be tree-shaken (legacy backward-compatibility with another project which consumes the one I am working on)

Simplified example of my code

main.js (entry file)

import { A } from 'foo';
console.log(A)

foo.js

export const A = 1;
export const B = 1;
export const C = 1;

Rollup output /build/foo.js

const A = 1;

export { A };

A very important thing for me is to keep the ability of other codebases (which are using "my" components lib) to be able to import specific things from specific files, such as the above foo.js example

Question -
How do I keep the exports from being tree-shaken out of the output (only for *.constants.js in my real scenario)?

Rollup setup:

{
  input: 'src/main.js',
  output: {
    dir: 'build',
    format: 'es', // imperative
    chunkFileNames: '[name].js',
    entryFileNames: '[name].js',
    preserveModules: true,  // imperative
    preserveModulesRoot: 'src',  // imperative
    sourcemap: true,
    exports: 'named',
  }
}