nullary.js

const response = {
  settings: {
    nullValue: null,
    height: 400,
    animationDuration: 0,
    headerText: '',
    showSplashScreen: false
  }
};

// result: 'some other default'
const undefinedValue = response.settings.undefinedValue ?? 'some other default'; 

// result: 'some other default'
const nullValue = response.settings.nullValue ?? 'some other default'; 

// result: ''
const headerText = response.settings.headerText ?? 'Hello, world!'; 

// result: 0
const animationDuration = response.settings.animationDuration ?? 300;

// result: false
const showSplashScreen = response.settings.showSplashScreen ?? true;