From 780dc0504b84cf8a1c67aa3889fef8e80962c22c Mon Sep 17 00:00:00 2001
From: Peter Staples <staplespeter.ni@gmail.com>
Date: Sat, 15 Oct 2022 00:10:44 +0100
Subject: [PATCH] bug-13140-001 Re-added spyOn support for function exports
 exposed using getters

---
 packages/jest-mock/src/index.ts | 82 ++++++++++++++++++---------------
 1 file changed, 44 insertions(+), 38 deletions(-)

diff --git a/packages/jest-mock/src/index.ts b/packages/jest-mock/src/index.ts
index 408690efaaab..f4c9b5776034 100644
--- a/packages/jest-mock/src/index.ts
+++ b/packages/jest-mock/src/index.ts
@@ -1193,72 +1193,78 @@ export class ModuleMocker {
           ${this._typeOf(descriptor?.[accessType])} given instead`,
         );
       }
-    } else if (typeof descriptor.value !== 'function') {
+    } else if (
+      (descriptor.value && typeof descriptor.value !== 'function') ||
+      (descriptor.get && typeof descriptor.get !== 'function')
+    ) {
       throw new Error(
         `Cannot spy the ${String(
           methodKey,
         )} property because it is not a function; ${this._typeOf(
-          descriptor.value,
+          descriptor.value ? descriptor.value : descriptor.get,
         )} given instead`,
       );
     }
 
+    const isMethodOwner = Object.prototype.hasOwnProperty.call(
+      object,
+      methodKey,
+    );
     let mock: Mock;
 
-    if (accessType == 'get' && descriptor['get']) {
-      const originalAccessor = descriptor['get'];
-      mock = this._makeComponent(
-        {
-          type: 'function',
-        },
-        () => {
-          descriptor![accessType] = originalAccessor;
+    if (accessType == 'get' && descriptor.get) {
+      const originalAccessor = descriptor.get;
+      mock = this._makeComponent({type: 'function'}, () => {
+        if (isMethodOwner) {
+          descriptor!.get = originalAccessor;
           Object.defineProperty(object, methodKey, descriptor!);
-        },
-      );
+        } else {
+          delete object[methodKey];
+        }
+      });
 
-      descriptor[accessType] = mock;
+      descriptor.get = mock;
       mock.mockImplementation(function (this: unknown) {
         return originalAccessor.call(this);
       });
       Object.defineProperty(object, methodKey, descriptor);
-    } else if (accessType == 'set' && descriptor['set']) {
-      const originalAccessor = descriptor['set'];
-      mock = this._makeComponent(
-        {
-          type: 'function',
-        },
-        () => {
-          descriptor![accessType] = originalAccessor;
+    } else if (accessType == 'set' && descriptor.set) {
+      const originalAccessor = descriptor.set;
+      mock = this._makeComponent({type: 'function'}, () => {
+        if (isMethodOwner) {
+          descriptor!.set = originalAccessor;
           Object.defineProperty(object, methodKey, descriptor!);
-        },
-      );
+        } else {
+          delete object[methodKey];
+        }
+      });
 
-      descriptor[accessType] = mock;
+      descriptor.set = mock;
       mock.mockImplementation(function (this: unknown) {
         return originalAccessor.call(this, arguments[0]);
       });
       Object.defineProperty(object, methodKey, descriptor);
+    } else if (descriptor.get) {
+      const originalGet = descriptor.get;
+      mock = this._makeComponent({type: 'function'}, () => {
+        descriptor!.get = originalGet;
+        Object.defineProperty(object, methodKey, descriptor!);
+      });
+      descriptor.get = () => mock;
+      Object.defineProperty(object, methodKey, descriptor);
     } else {
       const isMethodOwner = Object.prototype.hasOwnProperty.call(
         object,
         methodKey,
       );
       const original = descriptor;
-
-      mock = this._makeComponent(
-        {
-          type: 'function',
-        },
-        () => {
-          if (isMethodOwner) {
-            object[methodKey] = original.value;
-          } else {
-            delete object[methodKey];
-          }
-        },
-      );
-
+      mock = this._makeComponent({type: 'function'}, () => {
+        if (isMethodOwner) {
+          object[methodKey] = original.value;
+        } else {
+          delete object[methodKey];
+        }
+      });
       // @ts-expect-error overriding original method with a Mock
       object[methodKey] = mock;
       mock.mockImplementation(function (this: unknown) {