diff --git a/types/fs-promise/fs-promise-tests.ts b/types/fs-promise/fs-promise-tests.ts
index 43decbd256..51da06bb05 100644
--- a/types/fs-promise/fs-promise-tests.ts
+++ b/types/fs-promise/fs-promise-tests.ts
@@ -1,19 +1,19 @@
 import * as fs from "fs-promise";
 
-var src: string;
-var dst: string;
-var dir: string;
-var path: string;
-var data: any;
-var writeOptions: fs.WriteOptions;
-var writeJsonOptions: fs.WriteJsonOptions = {
+let src: string;
+let dst: string;
+let dir: string;
+let path: string;
+let data: any;
+let writeOptions: fs.WriteOptions;
+const writeJsonOptions: fs.WriteJsonOptions = {
     spaces: 2,
     replacer(key, value) {
         src = key;
         return value;
     }
 };
-var readJsonOptions: fs.ReadJsonOptions;
+let readJsonOptions: fs.ReadJsonOptions;
 
 async function test() {
     await fs.copy(src, dst);
diff --git a/types/fs-promise/index.d.ts b/types/fs-promise/index.d.ts
index 2038190ca1..6455018e5c 100644
--- a/types/fs-promise/index.d.ts
+++ b/types/fs-promise/index.d.ts
@@ -27,7 +27,7 @@ export interface WriteJsonOptions extends WriteOptions {
 export interface ReadJsonOptions {
     encoding: string;
     flag?: string;
-    reviver: (key: any, value: any) => any;
+    reviver(key: any, value: any): any;
 }
 
 export function copy(src: string, dst: string): Promise<void>;