I was trying to test a func using jest where I need to mock webpack defined global to test all the cases. I was unale to do so.

// webpack.config.js

...
new webpack.DefinePlugin({
__ENV__: `'${process.env.NODE_ENV}'`
}),
...

// commonUtil.js

const log = __ENV__ !== envs.PROD ? console.log.bind(console) : () => {};

// commonUtil.jest.js

describe('commonUtils', () => {
  const test = 'test';

  it('should log to the console in non-production environment', () => {
    __ENV__ = envs.PROD;
    log(test);
  });

 it('should log to the console in non-production environment', () => {
    __ENV__ = envs.DEV;
    log(test);
  });
});