Wrong type definition of args of move function

[kouhei]

Description

2nd and 3rd args of move function(defined at mock-interactions.js) are expected non-nullable objects have x and y properties.

export function move(node, fromXY, toXY, steps) {
  steps = steps || 5;
  var dx = Math.round((fromXY.x - toXY.x) / steps);
  var dy = Math.round((fromXY.y - toXY.y) / steps);
...

But according to type definition (mock-interactions.d.ts), it is nullable.

declare function move(node: Element, fromXY: object|null, toXY: object|null, ...