/FromFactor.ts(2,15): error TS2304: Cannot find name 'StringKeyOf'.
/FromFactor.ts(2,15): error TS4103: Type parameter 'TName' of exported mapped object type is using private name 'StringKeyOf'.


==== /Helpers.ts (0 errors) ====
    export type StringKeyOf<TObj> = Extract<string, keyof TObj>;
    
==== /FromFactor.ts (2 errors) ====
    export type RowToColumns<TColumns> = {
        [TName in StringKeyOf<TColumns>]: any;
                  ~~~~~~~~~~~
!!! error TS2304: Cannot find name 'StringKeyOf'.
                  ~~~~~~~~~~~
!!! error TS4103: Type parameter 'TName' of exported mapped object type is using private name 'StringKeyOf'.
    }