function winGetDrive(path) {
           ensureNotUNC(path);
           let index = path.indexOf(":");
           if (index <= 0) return null;
           return path.slice(0, index + 1);
         }
/**
          * Return the drive letter of a path, or |null| if the
          * path does not contain a drive letter.
          */
Return the drive letter of a path, or |null| if the
path does not contain a drive letter.
Return the drive letter of a path or |null| if the path does not contain a drive letter .
function winGetDrive(path) {
           ensureNotUNC(path);
           let index = path.indexOf(":");
           if (index <= 0) return null;
           return path.slice(0, index + 1);
         }
function winGetDrive ( path ) { ensureNotUNC ( path ) ; let index = path . indexOf ( ":" ) ; if ( index <= 0 ) return null ; return path . slice ( 0 , index + 1 ) ; }
Return the drive letter of a path, or |null| if the
 path does not contain a drive letter.
Return the drive letter of a path or |null| if the path does not contain a drive letter .