The alignment of the stroke with respect to the boundaries of the shape.
strokeAlign: "CENTER" | "INSIDE" | "OUTSIDE"
Center-aligned stroke means the center of the stroke falls exactly on the geometry. Inside-aligned stroke shifts the stroke so it lies completely inside the shape, and outside-aligned stroke is vice versa.
Inside and outside stroke are actually implemented by doubling the stroke weight and masking the stroke by the fill. This means inside-aligned stroke will never draw strokes outside the fill and outside-aligned stroke will never draw strokes inside the fill.