diff --git a/types/i18next-express-middleware/index.d.ts b/types/i18next-express-middleware/index.d.ts
index f9877b2659..d28a334429 100644
--- a/types/i18next-express-middleware/index.d.ts
+++ b/types/i18next-express-middleware/index.d.ts
@@ -5,104 +5,130 @@
 // TypeScript Version: 2.3
 
 declare namespace I18next {
-    interface I18nextOptions extends i18nextExpressMiddleware.I18nextOptions { }
+  interface I18nextOptions extends i18nextExpressMiddleware.I18nextOptions {}
 }
 
 declare namespace i18nextExpressMiddleware {
-    /**
-     * @summary Interface for Language detector options.
-     * @interface
-     */
-    interface LanguageDetectorOptions {
-        caches?: Array<string>|boolean;
-        cookieDomain?: string;
-        cookieExpirationDate?: Date;
-        lookupCookie?: string;
-        lookupFromPathIndex?: number;
-        lookupQuerystring?: string;
-        lookupSession?: string;
-        order?: Array<string>;
-    }
+  /**
+   * @summary Interface for Language detector options.
+   * @interface
+   */
+  interface LanguageDetectorOptions {
+    caches?: Array<string> | boolean
+    cookieDomain?: string
+    cookieExpirationDate?: Date
+    lookupCookie?: string
+    lookupFromPathIndex?: number
+    lookupQuerystring?: string
+    lookupSession?: string
+    order?: Array<string>
+  }
 
-    /**
-     * @summary i18next options.
-     * @interface
-     */
-    interface I18nextOptions {
-        detection?: LanguageDetectorOptions;
-    }
+  /**
+   * @summary i18next options.
+   * @interface
+   */
+  interface I18nextOptions {
+    detection?: LanguageDetectorOptions
+  }
 }
 
-declare module "i18next-express-middleware" {
-    import express = require("express");
-    import i18next = require("i18next");
+declare module 'i18next-express-middleware' {
+  import express = require('express')
+  import i18next = require('i18next')
+
+  /**
+   * @summary Interface for middleware to use i18next in express.js.
+   * @interface
+   */
+  export interface i18nextExpressMiddleware {
+    LanguageDetector(): express.Handler
+    missingKeyHandler(): express.Handler
+  }
+
+  /**
+   * @summary Interface for own detection functionality.
+   */
+  export interface i18nextCustomDetection {
+    name: string
+    lookup: (
+      req: express.Request,
+      res: express.Response,
+      options?: Object
+    ) => void
+    cacheUserLanguage: (
+      req: express.Request,
+      res: express.Response,
+      lng?: any,
+      options?: Object
+    ) => void
+  }
+
+  /**
+   * @summary Detects user language from current request.
+   * @class
+   */
+  export class LanguageDetector {
+    /**
+     * @summary Constructor.
+     * @constructor
+     * @param {any}     services    The services.
+     * @param {Object}  options     The options.
+     * @param {Object}  allOptions  The all options.
+     */
+    constructor(services?: any, options?: Object, allOptions?: Object)
 
     /**
-     * @summary Interface for middleware to use i18next in express.js.
-     * @interface
+     * @summary Adds detector.
+     * @param {i18nextCustomDetection} detector The detector to add.
      */
-    export interface i18nextExpressMiddleware {
-        LanguageDetector(): express.Handler;
-        missingKeyHandler(): express.Handler;
-    }
+    addDetector(detector: i18nextCustomDetection): void
+
+    // NOTE: add documentation
+    cacheUserLanguage(
+      req: express.Request,
+      res: express.Response,
+      detectionOrder: any
+    ): void
 
     /**
-     * @summary Interface for own detection functionality.
+     * @summary Detects the language.
+     * @param {Request}         req             The HTTP request.
+     * @param {Response}        res             The HTTP response.
+     * @param {detectionOrder}  detectionOrder  The detection order.
      */
-    export interface i18nextCustomDetection {
-        name: string;
-        lookup: (req: express.Request, res: express.Response, options?: Object) => void;
-        cacheUserLanguage: (req: express.Request, res: express.Response, lng?: any, options?: Object) => void;
-    }
+    detect(
+      req: express.Request,
+      res: express.Response,
+      detectionOrder: any
+    ): void
 
     /**
-     * @summary Detects user language from current request.
-     * @class
+     * @summary Initializes class.
+     * @param {any}     services    The services.
+     * @param {Object}  options     The options.
+     * @param {Object}  allOptions  The all options.
      */
-    export class LanguageDetector {
-        /**
-         * @summary Constructor.
-         * @constructor
-         * @param {any}     services    The services.
-         * @param {Object}  options     The options.
-         * @param {Object}  allOptions  The all options.
-         */
-        constructor(services?: any, options?: Object, allOptions?: Object);
+    init(services: any, options?: Object, allOptions?: Object): void
+  }
 
-        /**
-         * @summary Adds detector.
-         * @param {i18nextCustomDetection} detector The detector to add.
-         */
-        addDetector(detector: i18nextCustomDetection): void;
+  export function getResourcesHandler(
+    i18next: i18next.i18n,
+    options: Object
+  ): express.Handler
+  export function handle(
+    i18next: i18next.i18n,
+    options?: Object
+  ): express.Handler
 
-        // NOTE: add documentation
-        cacheUserLanguage(req: express.Request, res: express.Response, detectionOrder: any): void;
-
-        /**
-         * @summary Detects the language.
-         * @param {Request}         req             The HTTP request.
-         * @param {Response}        res             The HTTP response.
-         * @param {detectionOrder}  detectionOrder  The detection order.
-         */
-        detect(req: express.Request, res: express.Response, detectionOrder: any): void;
-
-        /**
-         * @summary Initializes class.
-         * @param {any}     services    The services.
-         * @param {Object}  options     The options.
-         * @param {Object}  allOptions  The all options.
-         */
-        init(services: any, options?: Object, allOptions?: Object): void;
-    }
-
-    export function getResourcesHandler(i18next: i18next.i18n, options: Object): express.Handler;
-    export function handle(i18next: i18next.i18n, options?: Object): express.Handler;
-
-    /**
-     * @summary Gets handler for missing key.
-     * @param {I18nextStatic}   i18next The i18next.
-     * @param {Object}          options The options.
-     * @return {express.Handler} The express handler.
-     */
-    export function missingKeyHandler(i18next: i18next.i18n, options: Object): express.Handler;
+  /**
+   * @summary Gets handler for missing key.
+   * @param {I18nextStatic}   i18next The i18next.
+   * @param {Object}          options The options.
+   * @return {express.Handler} The express handler.
+   */
+  export function missingKeyHandler(
+    i18next: i18next.i18n,
+    options?: Object
+  ): express.Handler
 }