components.js

import LoginScreenWithSideEffect from './LoginScreen';

module.exports = {
  get LoginScreen() {
    return LoginScreenWithSideEffect;
  },
};

constants.js

module.exports = {
  DEFAULT_COLOR: 'blue',
};

index.js

import Constants from './constants';
import Components from './components';

console.log(Constants.DEFAULT_COLOR);
render(new Components.Screen());

LoginScreen.js

import Constants from './Constants';

Constants.DEFAULT_COLOR = 'red';

export default function Screen() {}