The ornamental design for a handheld vacuumcleaner, as shown and described.
FIG. 1 is a perspective view of a handheld vacuum cleaner showing our new design;
FIG. 2 is a top plan view thereof;
FIG. 3 is a bottom plan view thereof;
FIG. 4 is a left side elevation view thereof;
FIG. 5 is a right side elevation view thereof;
FIG. 6 is a rear elevation view thereof; and,
FIG. 7 is a front elevation view thereof.
The dashed broken lines in the drawings are for the purpose of illustrating unclaimed portions of the handheld vacuum cleaner and form no part of the claimed design.