How to maximize the reuse of code in beforeRouteEnter and beforeRouteUpdate

[rubyLiuqq]

Version
3.0.1

Reproduction link
https://github.com/vuejs/vue-router/blob/dev/src/util/push-state.js#L44

Steps to reproduce
Run application into iframe

What is expected?
Please, add the way to setup window.top in VueRouter

What is actually happening?
const history = window.history
is used
should be way to use
const history = window.top.history
via some flag

[vue-bot]

Hello, your issue has been closed because it does not conform to our issue requirements. In order to ensure every issue provides the necessary information for us to investigate, we require the use of the Issue Helper when creating new issues. Thank you!

[rubyLiuqq]

To see #1582