simplify ssr initialization

Author: yyx990803

flow/declarations.js

@@ -5,6 +5,8 @@ declare module 'path-to-regexp' {
   }
 }
 
+declare var __VUE_SSR_CONTEXT__: any;
+
 declare type RouterOptions = {
   routes?: Array<RouteConfig>;
   mode?: string;

src/history/abstract.js

@@ -1,4 +1,5 @@
 /* @flow */
+/* globals __VUE_SSR_CONTEXT__ */
 
 import type VueRouter from '../index'
 import { History } from './base'
@@ -43,13 +44,10 @@ export class AbstractHistory extends History {
     })
   }
 
-  setInitialRoute (route: Route) {
-    this.current = route
-    this.stack = [this.current]
-    this.index = 0
-  }
-
   getLocation () {
-    return '/'
+    return (
+      typeof __VUE_SSR_CONTEXT__ !== 'undefined' &&
+      __VUE_SSR_CONTEXT__.url
+    ) || '/'
   }
 }

src/index.js

@@ -98,16 +98,6 @@ export default class VueRouter {
     this.go(1)
   }
 
-  setInitialLocation (location: RawLocation) {
-    const route = this.match(location)
-    if (this.history instanceof AbstractHistory) {
-      this.history.setInitialRoute(route)
-    }
-    if (this.app) {
-      this.app._route = route
-    }
-  }
-
   getMatchedComponents (): Array<any> {
     if (!this.currentRoute) {
       return []