const user = { name: 'Sarah', age: 0 };
const config = { theme: '', debug: false };

const result1 = user.age || 25;
const result2 = user.name && user.name.toUpperCase();
const result3 = config.theme || 'light';
const result4 = config.debug && console.log('Debug mode') || 'disabled';

console.log(result1);
console.log(result2);
console.log(result3);
console.log(result4);