get path() {
    // @ts-ignore _item is defined because target is integrated
    return getPathTo(this.currentTarget, this.target);
  }
Computes the path from `y` to the changed type.

@todo v14 should standardize on path: Array<{parent, index}> because that is easier to work with.

The following property holds:
@example
  let type = y
  event.path.forEach(dir => {
    type = type.get(dir)
  })
  type === event.target // => true