diff --git a/types/webpack/index.d.ts b/types/webpack/index.d.ts
index 07fa5644b1..afbbbf3928 100644
--- a/types/webpack/index.d.ts
+++ b/types/webpack/index.d.ts
@@ -5,6 +5,7 @@
 //                 Boris Cherny <https://github.com/bcherny>
 //                 Tommy Troy Lin <https://github.com/tommytroylin>
 //                 Mohsen Azimi <https://github.com/mohsen1>
+//                 Jonathan Creamer <https://github.com/jcreamer898>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 
 /// <reference types="node" />
@@ -834,9 +835,9 @@ declare namespace webpack {
 
     class HashedModuleIdsPlugin extends Plugin {
         constructor(options?: {
-            hashFunction: string,
-			hashDigest: string,
-			hashDigestLength: number
+            hashFunction?: string,
+            hashDigest?: string,
+            hashDigestLength?: number
         });
     }
 
diff --git a/types/webpack/webpack-tests.ts b/types/webpack/webpack-tests.ts
index 6c7095483d..7db91f59d9 100644
--- a/types/webpack/webpack-tests.ts
+++ b/types/webpack/webpack-tests.ts
@@ -424,6 +424,12 @@ plugin = new webpack.LoaderOptionsPlugin({
 plugin = new webpack.EnvironmentPlugin(['a', 'b']);
 plugin = new webpack.EnvironmentPlugin({a: true, b: 'c'});
 plugin = new webpack.ProgressPlugin((percent: number, message: string) => {});
+plugin = new webpack.HashedModuleIdsPlugin();
+plugin = new webpack.HashedModuleIdsPlugin({
+    hashFunction: 'sha256',
+    hashDigest: 'hex',
+    hashDigestLength: 20
+});
 
 //
 // http://webpack.github.io/docs/node.js-api.html