Add TypeEqual generic type

README.md

@@ -18,9 +18,12 @@ npm install ts-expect --save
 ## Usage
 
 ```ts
-import { expectType, TypeOf } from "ts-expect";
+import { expectType, TypeOf, TypeEqual } from "ts-expect";
 
 expectType<string>(123); // Compiler error!
+
+expectType<TypeOf<number, 123>>(true);
+expectType<TypeEqual<"test", "test">>(true);
 ```
 
 ### Examples

src/index.spec.ts

@@ -1,4 +1,4 @@
-import { expectType, TypeOf } from "./index";
+import { expectType, TypeOf, TypeEqual } from "./index";
 
 describe("ts expect", () => {
   it("should expect types", () => {
@@ -10,7 +10,29 @@ describe("ts expect", () => {
     const result = expectType("");
 
     expect(result).toEqual(undefined);
+  });
+
+  describe("TypeOf", () => {
+    it("should support type of checks", () => {
+      expectType<TypeOf<number, 123>>(true);
+      expectType<TypeOf<123, number>>(false);
+      expectType<TypeOf<string, "test">>(true);
+      expectType<TypeOf<"test", string>>(false);
+    });
+  });
+
+  describe("TypeEqual", () => {
+    it("should check types are equal", () => {
+      expectType<TypeEqual<123, 123>>(true);
+      expectType<TypeEqual<123, number>>(false);
+      expectType<TypeEqual<number, 123>>(false);
+      expectType<TypeEqual<number, number>>(true);
+
+      expectType<TypeEqual<false, true>>(false);
+      expectType<TypeEqual<false, boolean>>(false);
 
-    expectType<TypeOf<typeof result, void>>(true);
+      expectType<TypeEqual<1 | 2, 1>>(false);
+      expectType<TypeEqual<1 | 2, 1 | 2>>(true);
+    });
   });
 });

src/index.ts

@@ -3,6 +3,11 @@
  */
 export type TypeOf<T, U> = Exclude<U, T> extends never ? true : false;
 
+/**
+ * Checks that `T` is equal to `U`.
+ */
+export type TypeEqual<T, U> = Exclude<T, U> extends never ? Exclude<U, T> extends never ? true : false : false;
+
 /**
  * Assert the parameter is of a specific type.
  */