diff --git a/memoizee/index.d.ts b/memoizee/index.d.ts
index 125b34f264..456641dc59 100644
--- a/memoizee/index.d.ts
+++ b/memoizee/index.d.ts
@@ -3,47 +3,27 @@
 // Definitions by: Juan Picado <https://github.com/juanpicado>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 
-/**
- * Resolver options
- * @interface RevolversArray
- */
-interface RevolversArray {
-  [index: number]: {};
+declare namespace memoizee {
+  interface Options {
+    length?: number;
+    maxAge?: number;
+    max?: number;
+    preFetch?: number | true;
+    promise?: boolean;
+    dispose?: (value: any) => void;
+    async?: boolean;
+    primitive?: boolean;
+    normalizer?: (value: any) => void;
+    resolvers?: Array<(arg: any) => any>;
+  }
+
+  interface Memoized<F> {
+    delete: F;
+    clear: F & (() => void);
+  }
 }
 
-/**
- * List of options
- * @interface IMemoizeeOptions
- */
-interface IMemoizeeOptions {
-  length?: number;
-  maxAge?: number;
-  max?: number;
-  preFetch?: number;
-  promise?: boolean;
-  dispose?: (value: any) => void;
-  async?: boolean;
-  primitive?: boolean;
-  normalizer?: (value: any ) => void;
-  resolvers?: RevolversArray;
-}
-
-/**
- * Main interface functions
- * @interface IMemoizee
- * @extends {Function}
- */
-interface IMemoizee extends Function {
-  delete: (...params: any[]) => void;
-  clear: (...params: any[]) => void;
-}
-
-/**
- * Memoize function
- * @param {*} f
- * @param {IMemoizeeOptions} [options]
- * @returns {IMemoizee}
- */
-declare function memoizee(f: (...params: any[]) => void, options?: IMemoizeeOptions): IMemoizee;
+// tslint:disable:forbidden-types
+declare function memoizee<F extends Function>(f: F, options?: memoizee.Options): F & memoizee.Memoized<F>;
 
 export = memoizee;
diff --git a/memoizee/memoizee-tests.ts b/memoizee/memoizee-tests.ts
index 138a605712..e8e73a2d6a 100644
--- a/memoizee/memoizee-tests.ts
+++ b/memoizee/memoizee-tests.ts
@@ -1,6 +1,6 @@
 import memoize = require('memoizee');
 
-var fn = function (one:any, two:any, three:any) { /* ... */ };
+var fn = function (one: string, two?: number, three?: any) { /* ... */ };
 
 let memoized = memoize(fn);
 memoized('foo', 3, 'bar');
@@ -23,7 +23,7 @@ var foo3 = memoized('foo', 3);
 var bar7 = memoized('bar', 7);
 memoized.clear('foo', 3); // Dispose called with foo3 value
 memoized.clear('bar', 7); // Dispose called with bar7 value
-memoized.delete('foo', true);
+memoized.delete('foo', 0);
 var mFn = memoize(function (hash:any) {
     // body of memoized function
 }, { normalizer: function (args:any) {
@@ -34,17 +34,18 @@ var mFn = memoize(function (hash:any) {
 mFn({ foo: 'bar' });
 
 memoized = memoize(fn, { length: 2, resolvers: [String, Boolean] });
-memoized(12, [1,2,3].length);
-memoized("12", true);
-memoized({ toString: function () { return "12"; } }, {});
+memoized(String(12), [1,2,3].length);
+memoized("12", Number(true));
+memoized(String({ toString: function () { return "12"; } }), Number({}));
 
-var afn = function (a:number, b:number) {
-    return new Promise(function (res) { res(a + b); });
-};
-memoized = memoize(afn, { promise: true });
-
-memoized(3, 7);
-memoized(3, 7);
+{
+    var afn = function (a:number, b:number) {
+        return new Promise(function (res) { res(a + b); });
+    };
+    let memoized = memoize(afn, { promise: true });
+    memoized(3, 7);
+    memoized(3, 7);
+}
 
 memoized = memoize(fn, { maxAge: 1000, preFetch: 0.6 });
 
diff --git a/memoizee/tsconfig.json b/memoizee/tsconfig.json
index 68b204fbd9..c2ccff1cab 100644
--- a/memoizee/tsconfig.json
+++ b/memoizee/tsconfig.json
@@ -3,6 +3,7 @@
         "module": "commonjs",
         "target": "es6",
         "noImplicitAny": true,
+        "noImplicitThis": true,
         "strictNullChecks": true,
         "baseUrl": "../",
         "typeRoots": [