diff --git a/package-lock.json b/package-lock.json
index 09d5ff18..fe91a380 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -4683,9 +4683,9 @@
       }
     },
     "typescript": {
-      "version": "2.4.2",
-      "resolved": "https://registry.npmjs.org/typescript/-/typescript-2.4.2.tgz",
-      "integrity": "sha1-+DlfhdRZJ2BnyYiqQYN6j4KHCEQ=",
+      "version": "2.7.2",
+      "resolved": "https://registry.npmjs.org/typescript/-/typescript-2.7.2.tgz",
+      "integrity": "sha512-p5TCYZDAO0m4G344hD+wx/LATebLWZNkkh2asWUFqSsD2OrDNhbAHuSjobrmsUmdzjJjEeZVU9g1h3O6vpstnw==",
       "dev": true
     },
     "typings-tester": {
diff --git a/package.json b/package.json
index 1b676117..4c07387a 100644
--- a/package.json
+++ b/package.json
@@ -60,7 +60,7 @@
     "rimraf": "^2.6.1",
     "rollup": "^0.47.4",
     "rollup-plugin-babel": "^3.0.1",
-    "typescript": "^2.4.1",
+    "typescript": "^2.7.2",
     "typings-tester": "^0.2.2"
   },
   "jest": {
diff --git a/src/index.d.ts b/src/index.d.ts
index 83c4122c..655dec18 100644
--- a/src/index.d.ts
+++ b/src/index.d.ts
@@ -2,7 +2,7 @@ import { createSelector } from 'reselect';
 
 export type Selector<S, R> = (state: S) => R;
 
-export type Resolver<S> = (state: S, ...args: any[]) => number | string;
+export type Resolver<S> = (state: S, ...args: any[]) => any;
 
 export type CreateSelectorInstance = typeof createSelector;
 
@@ -29,7 +29,7 @@ export type OutputCachedSelector<S, R, C> = (resolver: Resolver<S>, optionsOrSel
 
 export type ParametricSelector<S, P, R> = (state: S, props: P, ...args: any[]) => R;
 
-export type ParametricResolver<S, P> = (state: S, props: P, ...args: any[]) => number | string;
+export type ParametricResolver<S, P> = (state: S, props: P, ...args: any[]) => any;
 
 export type OutputParametricSelector<S, P, R, C> = ParametricSelector<S, P, R> & {
   resultFunc: C;
@@ -599,9 +599,9 @@ export default function createCachedSelector<S, P, R1, R2, R3, R4, R5, R6, R7, R
             res7: R7, res8: R8, res9: R9, res10: R10, res11: R11, res12: R12) => T>;
 
 export interface ICacheObject {
-  set (key: string|number, selectorFn: any): void;
-  get (key: string|number): any;
-  remove (key: string|number): void;
+  set (key: any, selectorFn: any): void;
+  get (key: any): any;
+  remove (key: any): void;
   clear (): void;
 }
 
diff --git a/typescript_test/cache.ts b/typescript_test/cache.ts
index 3f26b2e0..cfdd621d 100644
--- a/typescript_test/cache.ts
+++ b/typescript_test/cache.ts
@@ -25,6 +25,8 @@ function testFlatCacheObject () {
   const cacheObject = new FlatCacheObject();
   cacheObject.set('foo', () => {});
   cacheObject.set(1, () => {});
+  // typings:expect-error
+  cacheObject.set({}, () => {});
   const result1: any = cacheObject.get('foo');
   const result2: any = cacheObject.get(2);
   cacheObject.remove('foo');
@@ -50,6 +52,8 @@ function testFifoCacheObject () {
   const cacheObject = new FifoCacheObject({ cacheSize: 10 });
   cacheObject.set('foo', () => {});
   cacheObject.set(1, () => {});
+  // typings:expect-error
+  cacheObject.set({}, () => {});
   const result1: any = cacheObject.get('foo');
   const result2: any = cacheObject.get(2);
   cacheObject.remove('foo');
@@ -75,6 +79,8 @@ function testLruCacheObject () {
   const cacheObject = new LruCacheObject({ cacheSize: 10 });
   cacheObject.set('foo', () => {});
   cacheObject.set(1, () => {});
+  // typings:expect-error
+  cacheObject.set({}, () => {});
   const result1: any = cacheObject.get('foo');
   const result2: any = cacheObject.get(2);
   cacheObject.remove('foo');
diff --git a/typescript_test/test.ts b/typescript_test/test.ts
index 1d3ec84f..f52152b0 100644
--- a/typescript_test/test.ts
+++ b/typescript_test/test.ts
@@ -301,18 +301,25 @@ function testArrayArgument() {
 }
 
 function testResolver() {
-  type State = {foo: string};
+  type State = {foo: string, obj: { bar: string } };
 
   const selector = createCachedSelector(
     (state: State) => state.foo,
     (state: never, arg1: number) => arg1,
     (state: never, arg1: number, arg2: number) => arg1 + arg2,
-    (foo, arg1, sum) => ({foo, arg1, sum}),
+    (foo, arg1, sum) => ({foo, arg1, sum})
   )(
-    (state: never, arg1: number, arg2: number) => arg1 + arg2,
+    (state: never, arg1: number, arg2: number) => arg1 + arg2
   );
 
-  selector({foo: 'fizz'}, 1, 2);
+  selector({foo: 'fizz', obj: { bar: 'bar' } }, 1, 2);
+
+  const selector2 = createCachedSelector(
+    (state: State) => state.obj,
+    obj => obj
+  )(
+    (state: never, obj) => obj
+  );
 }
 
 function testCustomSelectorCreator () {