function groupToMap groupToMap<T,K,V,>(keyOf: (row: T) => K,valueFrom: (row: T) => V,): unknown Group rows by a key, keeping only the chosen value from each row. Keys appear in first-occurrence order and each value list preserves input order. Type Parameters T K V Parameters keyOf: (row: T) => K valueFrom: (row: T) => V Return Type unknown