Jest Test Fails: Typeerror: Window. matchMedia Is Not a Function

I've been using this technique to solve a bunch of mocking problems.

describe("Test", () => {
  beforeAll(() => {
    Object.defineProperty(window, "matchMedia", {
      writable: true,
      value: jest.fn().mockImplementation(query => ({
        matches: false,
        media: query,
        onchange: null,
        addListener: jest.fn(), // Deprecated
        removeListener: jest.fn(), // Deprecated
        addEventListener: jest.fn(),
        removeEventListener: jest.fn(),
        dispatchEvent: jest.fn(),
      }))
    });
  });
});

Or, if you want to mock it all the time, you could put inside your mocks file called from your package.json: "setupFilesAfterEnv": "<rootDir>/src/tests/mocks.js",.

Reference: setupTestFrameworkScriptFile

I put a matchMedia stub in my Jest test file (above the tests), which allows the tests to pass:

window.matchMedia = window.matchMedia || function() {
    return {
        matches: false,
        addListener: function() {},
        removeListener: function() {}
    };
};

JESTS OFFICIAL WORKAROUND

is to create a mock file, called matchMedia.js and add the following code:

Object.defineProperty(window, 'matchMedia', {
    writable: true,
    value: jest.fn().mockImplementation((query) => ({
        matches: false,
        media: query,
        onchange: null,
        addListener: jest.fn(), // Deprecated
        removeListener: jest.fn(), // Deprecated
        addEventListener: jest.fn(),
        removeEventListener: jest.fn(),
        dispatchEvent: jest.fn(),
    })),
});

Then, inside your test file, import your mock import './matchMedia'; and as long as you import it in every use case, it should solve your problem.