fix: avoid first popstate event with async guard together (fix #1508) (…

…#1661)

src/history/html5.js

@@ -3,6 +3,7 @@
 import type Router from '../index'
 import { History } from './base'
 import { cleanPath } from '../util/path'
+import { START } from '../util/route'
 import { setupScroll, handleScroll } from '../util/scroll'
 import { pushState, replaceState } from '../util/push-state'
 
@@ -16,9 +17,18 @@ export class HTML5History extends History {
  setupScroll()
  }
 
+ const initLocation = getLocation(this.base)
  window.addEventListener('popstate', e => {
  const current = this.current
- this.transitionTo(getLocation(this.base), route => {
+
+ // Avoiding first `popstate` event dispatched in some browsers but first
+ // history route not updated since async guard at the same time.
+ const location = getLocation(this.base)
+ if (this.current === START && location === initLocation) {
+ return
+ }
+
+ this.transitionTo(location, route => {
  if (expectScroll) {
  handleScroll(router, route, current, true)
  }