avoid triggering beforeRouteUpdate and beforeRouteLeave for instances that are not even created yet (fix #1320)

Author: yyx990803

src/history/base.js

@@ -263,9 +263,11 @@ function extractUpdateHooks (updated: Array<RouteRecord>): Array<?Function> {
   return extractGuards(updated, 'beforeRouteUpdate', bindGuard)
 }
 
-function bindGuard (guard: NavigationGuard, instance: _Vue): NavigationGuard {
-  return function boundRouteGuard () {
-    return guard.apply(instance, arguments)
+function bindGuard (guard: NavigationGuard, instance: ?_Vue): ?NavigationGuard {
+  if (instance) {
+    return function boundRouteGuard () {
+      return guard.apply(instance, arguments)
+    }
   }
 }
 

test/unit/specs/error-handling.spec.js

@@ -8,6 +8,7 @@ describe('error handling', () => {
     const router = new VueRouter()
     const err = new Error('foo')
     router.beforeEach(() => { throw err })
+    router.onError(() => {})
 
     const onReady = jasmine.createSpy('ready')
     const onError = jasmine.createSpy('error')