Function resolve_pseudoref 

pub fn resolve_pseudoref(
    context: &GitContext,
    request: GitRequest,
) -> Option<String>

What: Resolve a pseudoref with git rev-parse --verify --quiet, or nothing when absent. Why: resolvePseudoref.

In TS you’d write (pseudocode):

async function resolvePseudoref({ gitPath, cwd, name }): Promise<string | typeof ENTRY_ABSENT>;