feat(types): NavigationGuardNext (#2497)

Author: beary

types/index.d.ts

@@ -12,5 +12,6 @@ export {
   RouteRecord,
   Location,
   Route,
-  NavigationGuard
-} from './router'
+  NavigationGuard,
+  NavigationGuardNext
+} from "./router";

types/router.d.ts

@@ -4,13 +4,15 @@ type Component = ComponentOptions<Vue> | typeof Vue | AsyncComponent
 type Dictionary<T> = { [key: string]: T }
 type ErrorHandler = (err: Error) => void
 
-export type RouterMode = 'hash' | 'history' | 'abstract'
-export type RawLocation = string | Location
-export type RedirectOption = RawLocation | ((to: Route) => RawLocation)
+export type RouterMode = "hash" | "history" | "abstract";
+export type RawLocation = string | Location;
+export type RedirectOption = RawLocation | ((to: Route) => RawLocation);
+export type NavigationGuardNext<V extends Vue = Vue> = (to?: RawLocation | false | ((vm: V) => any) | void) => void;
+                                
 export type NavigationGuard<V extends Vue = Vue> = (
   to: Route,
   from: Route,
-  next: (to?: RawLocation | false | ((vm: V) => any) | void) => void
+  next: NavigationGuardNext<V>
 ) => any
 
 export declare class VueRouter {