Exposing jest.runToFrame() from sinon/fake_timers

docs/JestObjectAPI.md

@@ -989,6 +989,16 @@ This function is not available when using legacy fake timers implementation.
 
 :::
 
+### `jest.runToFrame()`
+
+Advances all timers by the needed milliseconds to execute the next animation frame. This function is a helpful way to execute code that is scheduled using `requestAnimationFrame`.
+
+:::info
+
+This function is not available when using legacy fake timers implementation.
+
+:::
+
 ### `jest.clearAllTimers()`
 
 Removes any pending timers from the timer system.

docs/TimerMocks.md

@@ -167,6 +167,28 @@ it('calls the callback after 1 second via advanceTimersByTime', () => {
 
 Lastly, it may occasionally be useful in some tests to be able to clear all of the pending timers. For this, we have `jest.clearAllTimers()`.
 
+## Advance Timers to next Frame
+
+In applications, often you want to schedule work inside of an animation frame (via `requestAnimationFrame`). We expose a convenance method `jest.runToFrame()` to advance all timers enough milliseconds to execute all actively scheduled animation frames.
+
+```javascript
+jest.useFakeTimers();
+it('calls the animation frame callback after runToFrame()', () => {
+  const callback = jest.fn();
+
+  requestAnimationFrame(callback);
+
+  // At this point in time, the callback should not have been called yet
+  expect(callback).not.toBeCalled();
+
+  jest.runToFrame();
+
+  // Now our callback should have been called!
+  expect(callback).toBeCalled();
+  expect(callback).toHaveBeenCalledTimes(1);
+});
+```
+
 ## Selective Faking
 
 Sometimes your code may require to avoid overwriting the original implementation of one or another API. If that is the case, you can use `doNotFake` option. For example, here is how you could provide a custom mock function for `performance.mark()` in jsdom environment:

packages/jest-environment/src/index.ts

@@ -349,6 +349,14 @@ export interface Jest {
    * It is recommended to use `jest.mock()` instead. The `jest.mock()` API's second
    * argument is a module factory instead of the expected exported module object.
    */
+  /**
+   * Advances all timers by the needed milliseconds to execute the next animation frame.
+   * `runToFrame()` helpful way to execute code that is scheduled using `requestAnimationFrame`.
+   *
+   * @remarks
+   * Not available when using legacy fake timers implementation.
+   */
+  runToFrame(): void;
   setMock(moduleName: string, moduleExports: unknown): Jest;
   /**
    * Set the current system time used by fake timers. Simulates a user changing

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

@@ -103,6 +103,30 @@ describe('FakeTimers', () => {
       timers.useFakeTimers();
       expect(global.clearImmediate).not.toBe(origClearImmediate);
     });
+
+    it('mocks requestAnimationFrame if it exists on global', () => {
+      const global = {
+        Date,
+        clearTimeout,
+        requestAnimationFrame: () => -1,
+        setTimeout,
+      } as unknown as typeof globalThis;
+      const timers = new FakeTimers({config: makeProjectConfig(), global});
+      timers.useFakeTimers();
+      expect(global.requestAnimationFrame).toBeDefined();
+    });
+
+    it('mocks cancelAnimationFrame if it exists on global', () => {
+      const global = {
+        Date,
+        cancelAnimationFrame: () => {},
+        clearTimeout,
+        setTimeout,
+      } as unknown as typeof globalThis;
+      const timers = new FakeTimers({config: makeProjectConfig(), global});
+      timers.useFakeTimers();
+      expect(global.cancelAnimationFrame).toBeDefined();
+    });
   });
 
   describe('runAllTicks', () => {
@@ -570,6 +594,182 @@ describe('FakeTimers', () => {
     });
   });
 
+  describe('runToFrame', () => {
+    it('runs scheduled animation frames in order', () => {
+      const global = {
+        Date,
+        clearTimeout,
+        process,
+        requestAnimationFrame: () => -1,
+        setTimeout,
+      } as unknown as typeof globalThis;
+
+      const timers = new FakeTimers({config: makeProjectConfig(), global});
+      timers.useFakeTimers();
+
+      const runOrder: Array<string> = [];
+      const mock1 = jest.fn(() => runOrder.push('mock1'));
+      const mock2 = jest.fn(() => runOrder.push('mock2'));
+      const mock3 = jest.fn(() => runOrder.push('mock3'));
+
+      global.requestAnimationFrame(mock1);
+      global.requestAnimationFrame(mock2);
+      global.requestAnimationFrame(mock3);
+
+      timers.runToFrame();
+
+      expect(runOrder).toEqual(['mock1', 'mock2', 'mock3']);
+    });
+
+    it('should only run currently scheduled animation frames', () => {
+      const global = {
+        Date,
+        clearTimeout,
+        process,
+        requestAnimationFrame: () => -1,
+        setTimeout,
+      } as unknown as typeof globalThis;
+
+      const timers = new FakeTimers({config: makeProjectConfig(), global});
+      timers.useFakeTimers();
+
+      const runOrder: Array<string> = [];
+      function run() {
+        runOrder.push('first-frame');
+
+        // scheduling another animation frame in the first frame
+        global.requestAnimationFrame(() => runOrder.push('second-frame'));
+      }
+
+      global.requestAnimationFrame(run);
+
+      // only the first frame should be executed
+      timers.runToFrame();
+
+      expect(runOrder).toEqual(['first-frame']);
+
+      timers.runToFrame();
+
+      expect(runOrder).toEqual(['first-frame', 'second-frame']);
+    });
+
+    it('should allow cancelling of scheduled animation frames', () => {
+      const global = {
+        Date,
+        cancelAnimationFrame: () => {},
+        clearTimeout,
+        process,
+        requestAnimationFrame: () => -1,
+        setTimeout,
+      } as unknown as typeof globalThis;
+
+      const timers = new FakeTimers({config: makeProjectConfig(), global});
+      timers.useFakeTimers();
+
+      const runOrder: Array<string> = [];
+      const callback = () => runOrder.push('frame');
+
+      const timerId = global.requestAnimationFrame(callback);
+      global.cancelAnimationFrame(timerId);
+
+      // no frames should be executed
+      timers.runToFrame();
+
+      expect(runOrder).toEqual([]);
+    });
+
+    it('should only advance as much time is needed to get to the next frame', () => {
+      const global = {
+        Date,
+        cancelAnimationFrame: () => {},
+        clearTimeout,
+        process,
+        requestAnimationFrame: () => -1,
+        setTimeout,
+      } as unknown as typeof globalThis;
+
+      const timers = new FakeTimers({config: makeProjectConfig(), global});
+      timers.useFakeTimers();
+
+      const runOrder: Array<string> = [];
+      const start = global.Date.now();
+
+      const callback = () => runOrder.push('frame');
+      global.requestAnimationFrame(callback);
+
+      // Advancing timers less than a frame (which is 16ms)
+      timers.advanceTimersByTime(6);
+      expect(global.Date.now()).toEqual(start + 6);
+
+      // frame not yet executed
+      expect(runOrder).toEqual([]);
+
+      // move timers forward to execute frame
+      timers.runToFrame();
+
+      // frame has executed as time has moved forward 10ms to get to the 16ms frame time
+      expect(runOrder).toEqual(['frame']);
+      expect(global.Date.now()).toEqual(start + 16);
+    });
+
+    it('should execute any timers on the way to the animation frame', () => {
+      const global = {
+        Date,
+        cancelAnimationFrame: () => {},
+        clearTimeout,
+        process,
+        requestAnimationFrame: () => -1,
+        setTimeout,
+      } as unknown as typeof globalThis;
+
+      const timers = new FakeTimers({config: makeProjectConfig(), global});
+      timers.useFakeTimers();
+
+      const runOrder: Array<string> = [];
+
+      global.requestAnimationFrame(() => runOrder.push('frame'));
+
+      // scheduling a timeout that will be executed on the way to the frame
+      global.setTimeout(() => runOrder.push('timeout'), 10);
+
+      // move timers forward to execute frame
+      timers.runToFrame();
+
+      expect(runOrder).toEqual(['timeout', 'frame']);
+    });
+
+    it('should not execute any timers scheduled inside of a frame', () => {
+      const global = {
+        Date,
+        cancelAnimationFrame: () => {},
+        clearTimeout,
+        process,
+        requestAnimationFrame: () => -1,
+        setTimeout,
+      } as unknown as typeof globalThis;
+
+      const timers = new FakeTimers({config: makeProjectConfig(), global});
+      timers.useFakeTimers();
+
+      const runOrder: Array<string> = [];
+
+      global.requestAnimationFrame(() => {
+        runOrder.push('frame');
+        // scheduling a timer inside of a frame
+        global.setTimeout(() => runOrder.push('timeout'), 1);
+      });
+
+      timers.runToFrame();
+
+      // timeout not yet executed
+      expect(runOrder).toEqual(['frame']);
+
+      // validating that the timer will still be executed
+      timers.advanceTimersByTime(1);
+      expect(runOrder).toEqual(['frame', 'timeout']);
+    });
+  });
+
   describe('reset', () => {
     it('resets all pending setTimeouts', () => {
       const global = {
@@ -649,6 +849,25 @@ describe('FakeTimers', () => {
       timers.advanceTimersByTime(50);
       expect(mock1).toHaveBeenCalledTimes(0);
     });
+
+    it('resets all scheduled animation frames', () => {
+      const global = {
+        Date,
+        clearTimeout,
+        process,
+        requestAnimationFrame: () => -1,
+        setTimeout,
+      } as unknown as typeof globalThis;
+      const timers = new FakeTimers({config: makeProjectConfig(), global});
+      timers.useFakeTimers();
+
+      const mock1 = jest.fn();
+      global.requestAnimationFrame(mock1);
+
+      timers.reset();
+      timers.runAllTimers();
+      expect(mock1).toHaveBeenCalledTimes(0);
+    });
   });
 
   describe('runOnlyPendingTimers', () => {

packages/jest-fake-timers/src/__tests__/sinon-integration.test.ts

@@ -17,13 +17,15 @@ const mockWithGlobal = {
   install: mockInstall,
   timers: {
     Date: jest.fn(),
+    cancelAnimationFrame: jest.fn(),
     clearImmediate: jest.fn(),
     clearInterval: jest.fn(),
     clearTimeout: jest.fn(),
     hrtime: jest.fn(),
     nextTick: jest.fn(),
     performance: jest.fn(),
     queueMicrotask: jest.fn(),
+    requestAnimationFrame: jest.fn(),
     setImmediate: jest.fn(),
     setInterval: jest.fn(),
     setTimeout: jest.fn(),
@@ -57,13 +59,15 @@ describe('`@sinonjs/fake-timers` integration', () => {
       shouldClearNativeTimers: true,
       toFake: [
         'Date',
+        'cancelAnimationFrame',
         'clearImmediate',
         'clearInterval',
         'clearTimeout',
         'hrtime',
         'nextTick',
         'performance',
         'queueMicrotask',
+        'requestAnimationFrame',
         'setImmediate',
         'setInterval',
         'setTimeout',
@@ -93,12 +97,14 @@ describe('`@sinonjs/fake-timers` integration', () => {
       shouldAdvanceTime: true,
       shouldClearNativeTimers: true,
       toFake: [
+        'cancelAnimationFrame',
         'clearImmediate',
         'clearInterval',
         'clearTimeout',
         'hrtime',
         'performance',
         'queueMicrotask',
+        'requestAnimationFrame',
         'setImmediate',
         'setInterval',
         'setTimeout',
@@ -126,12 +132,14 @@ describe('`@sinonjs/fake-timers` integration', () => {
       shouldAdvanceTime: true,
       shouldClearNativeTimers: true,
       toFake: [
+        'cancelAnimationFrame',
         'clearImmediate',
         'clearInterval',
         'clearTimeout',
         'hrtime',
         'nextTick',
         'performance',
+        'requestAnimationFrame',
         'setImmediate',
         'setInterval',
         'setTimeout',
@@ -166,12 +174,14 @@ describe('`@sinonjs/fake-timers` integration', () => {
       shouldClearNativeTimers: true,
       toFake: [
         'Date',
+        'cancelAnimationFrame',
         'clearImmediate',
         'clearInterval',
         'clearTimeout',
         'nextTick',
         'performance',
         'queueMicrotask',
+        'requestAnimationFrame',
         'setImmediate',
         'setInterval',
         'setTimeout',

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

@@ -117,6 +117,12 @@ export default class FakeTimers {
     }
   }
 
+  runToFrame(): void {
+    if (this._checkFakeTimers()) {
+      this._clock.runToFrame();
+    }
+  }
+
   useRealTimers(): void {
     if (this._fakingTime) {
       this._clock.uninstall();