The ornamental design for a taillightbar for a vehicle thereof, as shown and described.
FIG. 1 is a front perspective view for a taillight bar for a vehicle showing my new design,
FIG. 2 is a rear perspective view thereof,
FIG. 3 is a front view thereof,
FIG. 4 is a rear view thereof,
FIG. 5 is a top view thereof,
FIG. 6 is a left-side view thereof; and,
FIG. 7 is a right-side view thereof.
In the drawings, the portion of the taillight bar for a vehicle shown in lighter gray scale represents environmental subject matter that forms no part of the claimed design.