### Version 3.4.0 ### Reproduction link [https://jsfiddle.net/herophuong/97bq4vmh/](https://jsfiddle.net/herophuong/97bq4vmh/) ### Steps to reproduce 1. Call `$router.push({path: '/', query: {q: undefined}})` ### What is expected? URL should be `/` ### What is actually happening? URL is now `/?q=undefined` --- Possibly due to fixing this issue: https://github.com/vuejs/vue-router/issues/2131 <!-- generated by vue-issues. DO NOT REMOVE -->