Jest – Mock a constant property from a module for a specific test

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File that exports a constant value that I want to mock:

// utils/deviceTypeUtils file
import DeviceInfo from 'react-native-device-info';

export const isTablet = DeviceInfo.isTablet();

In my test file, I use this code to mock the constant isTablet:

// file: deviceTypeUtils.spec
const DeviceTypeUtilsMock = jest.requireMock('../utils/deviceTypeUtils');
jest.mock('../utils/deviceTypeUtils', () => ({
  isTablet: false,
}));

describe('mock const example', () => {
  it('mock const `isTablet` to the value `true`', () => {
    DeviceTypeUtilsMock.isTablet = true;
  });

  it('mock const `isTablet` to the value `false`', () => {
    DeviceTypeUtilsMock.isTablet = false;
  });
});

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