message: refactor(router): remove ts check
diff: @@ -1057,7 +1057,7 @@ export function createRouter(options: RouterOptions): Router {
  null
  return nextTick()
  - .then(() => scrollBehavior!(to, from, scrollPosition))
  + .then(() => scrollBehavior(to, from, scrollPosition))
  .then(position => position && scrollToPosition(position))
  .catch(triggerError)
  }
  