the point to test
Optional vector: [number, number]an optional vector, used in the case that the point exists along an edge or a vertex.
the index of a face, or undefined if the point does not lie inside any face.
Given a point, get the index of a face that this point exists within. In the case when the point lies along an edge or vertex, an additional vector parameter can be used to nudge the point by a very tiny amount, then there will be a preference to return the index of the face which encloses the nudged point. This is a 2D-only method, any z-axis data will be ignored.
a FOLD object