The ornamental design for the top cap for an electroniccigarette, as shown and described.
FIG. 1 is a front view of the top cap for an electronic cigarette showing my new design, the left side, right side, and rear views are identical;
FIG. 2 is a top view thereof;
FIG. 3 is a bottom view thereof; and,
FIG. 4 is a front view thereof; showing the top cap for an electronic cigarette in a state of use, for clarity of disclosure, coupled to the body of an electronic cigarette.
The broken lines in the drawings depict the body of an electronic cigarette that forms no part of the claimed design.