const a = false || 0 || "" || null || "JavaScript";
console.log(a);

function Person(name) {
  this.name = name;
  this.sayName = () => console.log(this.name);
}

const person1 = new Person('David');
const person2 = { name: 'Not David', sayName: person1.sayName };

person2.sayName();

const factorial = (function () {
  const cache = {};
  return function inner(n) {
    if (n in cache) return cache[n];
    return (cache[n] = n <= 1 ? 1 : n * inner(n - 1));
  };
})();

console.log(factorial(5)); 
console.log(factorial(5));

const obj = { value: 10 };
const result = (obj.value += 5) && obj.value;
console.log(result);

async function test() {
  return (await Promise.resolve(0)) || 10;
}

test().then(console.log);

const arr = [1, 2, 3];
const copy = [...arr];
copy.push(4);

console.log(arr);
console.log(copy);