Simulate keydown on document for JEST unit testing

Question

Using JEST to unit test a component that has a keydown listener attached to the document.

How can I test this in JEST? How do I simulate t

Answer 1

Following @Iris Schaffer answer, If your code makes use of ctrl/alt/shift keys, you will need to init them, as well as mocking implementation of getModifierState method on KeyboardEvent

const keyboardEvent = new KeyboardEvent('keydown', { keyCode, shiftKey, altKey, ctrlKey });
jest.spyOn(keyboardEvent, 'getModifierState').mockImplementation((modifier) => {
     switch (modifier) {
          case 'Alt':
               return altKey;
          case 'Control':
               return ctrlKey;
          case 'Shift':
               return shiftKey;
     }
});