Example 2.ts

let mode: "idle" | "dragging" = "idle"
const dragHandler: InteractionHandler = {
  onDragStart(gesture, app) {
    if (intersection(gesture.elementsUnderCursor, app.selectedElements).size) {
      mode = "dragging";
    }
  },

  onPointerMove(gesture) {
    // ignore pointer-moves when we haven't started dragging
    if (mode !== "dragging") return;

    const delta = sub(gesture.current.point, gesture.start.point);
    transformSelectedElements(delta)
		
    // prevents other pointermove handlers acting (not important for this case)
    gesture.wasHandled();
  },

  onDragEnd() {
    mode = "idle";
  },
};

const selectionHandler: InteractionHandler = {
  onClick(gesture) {
    addElementToSelectionSet(gesture.topElement);
  },
};