const obj = { a: 1, b: 2 };
const proxy = new Proxy(obj, {
  get(target, prop) {
    return prop in target ? target[prop] : 0;
  }
});

console.log(proxy.a, proxy.b, proxy.c);

const array = [1, 2, 3];
array[10] = 4;

console.log(array.length);
console.log(array.includes(undefined));

const obj = {
  a: 1,
  b() {
    return this.a;
  }
};

const b = obj.b;
console.log(b.call({ a: 2 }));

const array = [1, 2, 3, 4, 5];
const result = array.some(n => n % 2 === 0) && array.every(n => n < 10);

console.log(result);

const obj1 = { a: 1, b: { c: 2 } };
const obj2 = { ...obj1 };

obj1.b.c = 3;

console.log(obj2.b.c);

const arr = [1, 2, 3, 4, 5];
const sliced = arr.slice(1, 3);
const spliced = arr.splice(1, 3);

console.log(sliced, spliced, arr);

const obj = { a: 1, b: 2 };
const obj2 = { ...obj, b: 3 };

const samePrototype = Object.getPrototypeOf(obj) === Object.getPrototypeOf(obj2);

console.log(samePrototype);