I have a module with a good handful of chunks A, B, C, and D, all of which rely on a shared utilities file which Rollup separately chunks.

Because this utilities file is only a couple of Kb, and because every single child chunk requires it, I want to merge this utilities file back into the main entrypoint. It does absolutely no good as a chunk on it’s own.

However, I can’t figure out how to do this. Rollup documents the manualChunks(id) option but it has absolutely no documentation on how you merge back into the entrypoint. Providing a generic name like index creates two index.<hash>.js files, one being the entrypoint and the second being my utilities file.

manualChunks(id) {
    if (id.includes('lib/utilities.js')) {
        return 'index';
    }
}

How can I force Rollup to hoist this module back up into the entrypoint?