[jest] limit type inference for spyOn getter/setter to non fonction p…

…roperties & spyOn method to function properties
DefinitelyTyped · Feb 8, 2019 · d4fe875 · villelahdenvuo · Feb 12, 2019 · antoinebrault
1 parent 5a0cb02
commit d4fe875
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Showing 2 changed files with 21 additions and 7 deletions.
diff --git a/types/jest/index.d.ts b/types/jest/index.d.ts
@@ -37,6 +37,9 @@ declare var xtest: jest.It;
 declare const expect: jest.Expect;
 
 type ArgsType<T> = T extends (...args: infer A) => any ? A : never;
+// see https://github.com/Microsoft/TypeScript/issues/25215
+type NonFunctionPropertyNames<T> = { [K in keyof T]: T[K] extends (...args: any[]) => any ? never : K }[keyof T] & string;
+type FunctionPropertyNames<T> = { [K in keyof T]: T[K] extends (...args: any[]) => any ? K : never }[keyof T] & string;
 
 interface NodeRequire {
     /**
@@ -215,9 +218,9 @@ declare namespace jest {
      *   spy.mockRestore();
      * });
      */
-    function spyOn<T extends {}, M extends keyof T>(object: T, method: M, accessType: 'get'): SpyInstance<T[M], []>;
-    function spyOn<T extends {}, M extends keyof T>(object: T, method: M, accessType: 'set'): SpyInstance<void, [T[M]]>;
-    function spyOn<T extends {}, M extends keyof T>(object: T, method: M): T[M] extends (...args: any[]) => any ? SpyInstance<ReturnType<T[M]>, ArgsType<T[M]>> : never;
+    function spyOn<T extends {}, M extends NonFunctionPropertyNames<T>>(object: T, method: M, accessType: 'get'): SpyInstance<T[M], []>;
+    function spyOn<T extends {}, M extends NonFunctionPropertyNames<T>>(object: T, method: M, accessType: 'set'): SpyInstance<void, [T[M]]>;
+    function spyOn<T extends {}, M extends FunctionPropertyNames<T>>(object: T, method: M): T[M] extends (...args: any[]) => any ? SpyInstance<ReturnType<T[M]>, ArgsType<T[M]>> : never;
     /**
      * Indicates that the module system should never return a mocked version of
      * the specified module from require() (e.g. that it should always return the real module).

diff --git a/types/jest/jest-tests.ts b/types/jest/jest-tests.ts
@@ -360,24 +360,35 @@ const spiedTarget = {
 
 class SpiedTargetClass {
     private _value = 3;
+    private _value2 = '';
     get value() {
         return this._value;
     }
     set value(value) {
         this._value = value;
     }
+    get value2() {
+        return this._value2;
+    }
+    set value2(value2) {
+        this._value2 = value2;
+    }
 }
 const spiedTarget2 = new SpiedTargetClass();
 
+// $ExpectError
+jest.spyOn(spiedTarget, "setValue", "get");
+// $ExpectError
+jest.spyOn(spiedTarget2, "value");
+
 const spy1 = jest.spyOn(spiedTarget, "returnsVoid");
-const spy2 = jest.spyOn(spiedTarget, "returnsVoid", "get");
 const spy3 = jest.spyOn(spiedTarget, "returnsString");
 const spy1Name: string = spy1.getMockName();
 
-const spy2Calls: any[][] = spy2.mock.calls;
+const spy1Calls: Array<[]> = spy1.mock.calls;
 
-spy2.mockClear();
-spy2.mockReset();
+spy1.mockClear();
+spy1.mockReset();
 
 const spy3Mock = spy3
     .mockImplementation(() => "")