Function rules_candidate_path 

pub fn rules_candidate_path(
    rules_path: &Path,
    repository_root: &Path,
) -> Option<Vec<u8>>

What: The rules file’s pathname as a candidate would carry it, when it lies inside the repository. Option<Vec<u8>> is “pathname bytes or nothing”. Why: A rules file tracked in the repository would match its own patterns, so its candidate is not scanned. A rules file outside the repository can never be a candidate, which is “nothing”.

In TS you’d write (pseudocode):

function rulesCandidatePath(rulesPath: string, repositoryRoot: string): string | undefined;