constructor( vertex, face ) {

		/**
		 * A reference to its destination vertex.
		 *
		 * @private
		 * @type {VertexNode}
		 */
		this.vertex = vertex;

		/**
		 * Reference to the previous half-edge of the same face.
		 *
		 * @private
		 * @type {?HalfEdge}
		 * @default null
		 */
		this.prev = null;

		/**
		 * Reference to the next half-edge of the same face.
		 *
		 * @private
		 * @type {?HalfEdge}
		 * @default null
		 */
		this.next = null;

		/**
		 * Reference to the twin half-edge to reach the opposite face.
		 *
		 * @private
		 * @type {?HalfEdge}
		 * @default null
		 */
		this.twin = null;

		/**
		 * A reference to its face.
		 *
		 * @private
		 * @type {Face}
		 */
		this.face = face;

	}
Constructs a new half edge.

@param {VertexNode} vertex - A reference to its destination vertex.
@param {Face} face - A reference to its face.