message: Fixing wheel events for Firefox
diff: @@ -130,10 +130,10 @@ export function getMouseCoords(e) {
  * @return {number} The wheel delta of the mouse.
  */
  export function getWheelDelta(e) {
  - if (typeof e.wheelDelta !== undefined)
  + if (typeof e.wheelDelta !== 'undefined')
  return e.wheelDelta;
  - if (typeof e.detail !== undefined)
  + if (typeof e.detail !== 'undefined')
  return -e.detail;
  throw new Error('sigma/captors/utils.getDelta: could not extract delta from event.');
  