fix(types): allow null/undefined in query params

fix #2605

Author: posva

types/router.d.ts

@@ -108,7 +108,7 @@ export interface Location {
   name?: string;
   path?: string;
   hash?: string;
-  query?: Dictionary<string | string[]>;
+  query?: Dictionary<string | (string | null)[] | null | undefined>;
   params?: Dictionary<string>;
   append?: boolean;
   replace?: boolean;
@@ -118,7 +118,7 @@ export interface Route {
   path: string;
   name?: string;
   hash: string;
-  query: Dictionary<string | string[]>;
+  query: Dictionary<string | (string | null)[]>;
   params: Dictionary<string>;
   fullPath: string;
   matched: RouteRecord[];

types/test/index.ts

@@ -105,7 +105,7 @@ const route: Route = router.currentRoute;
 const path: string = route.path;
 const name: string | undefined = route.name;
 const hash: string = route.hash;
-const query: string | string[] = route.query["foo"];
+const query: string | (string | null)[] | null = route.query["foo"];
 const params: string = route.params["bar"];
 const fullPath: string = route.fullPath;
 const redirectedFrom: string | undefined = route.redirectedFrom;
@@ -149,6 +149,9 @@ router.push({
   },
   query: {
     bar: "bar",
+    empty: null,
+    removed: undefined,
+    withEmpty: ["1", null],
     foo: ["foo1", "foo2"]
   },
   hash: "hash"