看源碼的時候看到這個屬性：
新手自然不知道這個是什么東西了，查了下vue API：
https://router.vuejs.org/en/advanced/scroll-behavior.html
上面這個的意思就是當轉到一個新的頁面時，定位到最頂端。
Scroll Behavior
When using client-side routing, we may want to scroll to top when navigating to a new route, or preserve the scrolling position of history entries just like real page reload does. vue-router allows you to achieve these and even better, allows you to completely customize the scroll behavior on route navigation.
Note: this feature only works in HTML5 history mode.
When creating the router instance, you can provide the scrollBehavior function:
const router = new VueRouter({ routes: [...], scrollBehavior (to, from, savedPosition) { // return desired position } })The scrollBehavior function receives the to and from route objects. The third argument, savedPosition, is only available if this is a popstate navigation (triggered by the browser's back/forward buttons).
The function can return a scroll position object. The object could be in the form of:
{ x: number, y: number }{ selector: string }
If a falsy value or an empty object is returned, no scrolling will happen.
For example:
scrollBehavior (to, from, savedPosition) { return { x: 0, y: 0 } } This will simply make the page scroll to top for all route navigations.
Returning the savedPosition will result in a native-like behavior when navigating with back/forward buttons:
scrollBehavior (to, from, savedPosition) { if (savedPosition) { return savedPosition } else { return { x: 0, y: 0 } } } If you want to simulate the "scroll to anchor" behavior:
scrollBehavior (to, from, savedPosition) { if (to.hash) { return { selector: to.hash } } } We can also use route meta fields to implement fine-grained scroll behavior control. Check out a full example here.