Add options object with ignore property to modern useFakeTimers function

CHANGELOG.md

@@ -1,6 +1,7 @@
 ## master
 
 ### Features
+- `[@jest/fake-timers]` Add options object with ignore property to modern useFakeTimers function. ([#11661](https://github.com/facebook/jest/pull/11661))
 
 ### Fixes
 

packages/jest-fake-timers/src/__tests__/modernFakeTimers.test.ts

@@ -798,6 +798,30 @@ describe('FakeTimers', () => {
       expect(global.setImmediate).not.toBe(nativeSetImmediate);
       expect(global.clearImmediate).not.toBe(nativeClearImmediate);
     });
+
+    it('ignores timer functions from the ignore option', () => {
+      const nativeSetTimeout = jest.fn();
+      const nativeClearTimeout = jest.fn();
+      const nativeNextTick = jest.fn();
+      process.nextTick = nativeNextTick;
+      const global = {
+        Date,
+        clearTimeout: nativeClearTimeout,
+        process,
+        setTimeout: nativeSetTimeout,
+      };
+
+      const timers = new FakeTimers({global});
+      timers.useFakeTimers({
+        ignore: ['nextTick', 'clearTimeout'],
+      });
+
+      // Ignored functions don't get mocked
+      expect(global.process.nextTick).toBe(nativeNextTick);
+      expect(global.clearTimeout).toBe(nativeClearTimeout);
+      // check if other functions are still being mocked
+      expect(global.setTimeout).not.toBe(nativeSetTimeout);
+    });
   });
 
   describe('getTimerCount', () => {

packages/jest-fake-timers/src/modernFakeTimers.ts

@@ -12,6 +12,10 @@ import {
 } from '@sinonjs/fake-timers';
 import {StackTraceConfig, formatStackTrace} from 'jest-message-util';
 
+interface ModernFakeTimersOptions {
+  ignore?: Array<string>;
+}
+
 export default class FakeTimers {
   private _clock!: InstalledClock;
   private _config: StackTraceConfig;
@@ -93,11 +97,13 @@ export default class FakeTimers {
     }
   }
 
-  useFakeTimers(): void {
+  useFakeTimers(options: ModernFakeTimersOptions = {}): void {
     if (!this._fakingTime) {
-      const toFake = Object.keys(this._fakeTimers.timers) as Array<
-        keyof FakeTimerWithContext['timers']
-      >;
+      const toFake = Object.keys(this._fakeTimers.timers).filter(
+        // This is a simple attempt to fix the issue when using fakeTimers in combination with promises
+        // Developers can now add the nextTick function to the list timers not to mock
+        timerFunc => !(options?.ignore || []).includes(timerFunc),
+      ) as Array<keyof FakeTimerWithContext['timers']>;
 
       this._clock = this._fakeTimers.install({
         loopLimit: this._maxLoops,