if (false) {
    function foo() {
        return 1;
    }
}

console.log(foo());

function main({ x, y } = { x: 1, y: 2 }) {
   console.log(x, y);
}

main({ x: 5 });

const obj = { name: 'Alice', age: 30 };  
const handler = {
  get(target, prop) {
    return prop in target ? target[prop] : `Property '${prop}' doesn't exist`;
  }
};

const proxy = new Proxy(obj, handler);

const descriptors = Object.getOwnPropertyDescriptors(obj);
Reflect.defineProperty(obj, 'city', {
  value: 'New York',
  enumerable: false
});

console.log(proxy.city, proxy.country);

let obj = { a: 1 };
let proto = { b: 2 };

Object.setPrototypeOf(obj, proto);

for (let key in obj) {
  console.log(key);
}

function asyncQuiz() {
  return new Promise((resolve) => {
    setTimeout(() => resolve('Hello'), 1000);
  });
}

async function runAsyncQuiz() {
  const result = await asyncQuiz();
  console.log(result);
}

runAsyncQuiz();
console.log('World');

const text = 'Today is 2023-12-31 and tomorrow is 2024-01-01';
const dateRegex = /(\d{4})-(\d{2})-(\d{2})/g;

let result = '';
let match;

while ((match = dateRegex.exec(text)) !== null) {
  const [fullMatch, year, month, day] = match;
  result += `${day}/${month}/${year.slice(2)} `;
}

console.log(result.trim());

function tag(strings, ...values) {
  return strings.reduce((acc, str, i) => {
    return acc + str + (values[i] ? values[i].toUpperCase() : '');
  }, '');
}

const first = "hello";
const second = "world";

const result = tag`${first} and ${second} are great!`;

console.log(result);

console.log(MyClass);
class MyClass {
  constructor() {
    this.value = 42;
  }
}

function* counter() {
  let count = 1;
  while (true) {
    const reset = yield count++;
    if (reset) {
      count = 1;
    }
  }
}

const gen = counter();
console.log(gen.next().value);
console.log(gen.next().value);
console.log(gen.next(true).value);
console.log(gen.next().value);

const obj = Object.freeze({
  a: [1, 2, 3],
  b: {
    c: 4
  }
});

obj.a.push(4);
obj.b.c = 5;

console.log(obj.a);
console.log(obj.b.c);

function* alternatingGenerator() {
  yield 1;
  yield 2;
  yield 3;
}

const gen = alternatingGenerator();
const result = [gen.next().value, gen.next().value, gen.next().value].reduce((acc, curr) => acc + curr, 0);

console.log(result);

function outer() {
  console.log(typeof inner);
  console.log(typeof inner2);
  
  var inner = function() {
    return 'Inside inner';
  };
  
  function inner2() {
    return 'Inside inner2';
  }
  
  console.log(typeof inner);
  console.log(typeof inner2);
}

outer();

const numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];

const result = numbers
  .filter(num => num % 2 === 0)
  .map(num => num * 2)
  .reduce((acc, curr, idx, arr) => {
    if (idx === arr.length - 1) {
      return (acc + curr) / arr.length;
    }
    return acc + curr;
  }, 0);

console.log(result);

const obj = {
   x: 10,
   foo() {
      setTimeout(function() {
         console.log(this.x);
      }, 1000);
   }
};
obj.foo();

const cache = new WeakMap();

const user1 = { name: 'Alice' };
const user2 = { name: 'Bob' };

cache.set(user1, { lastLogin: 'yesterday' });
cache.set(user2, { lastLogin: 'today' });

const result = [];
result.push(cache.has(user1));
result.push(cache.get(user2).lastLogin);

let user3 = { name: 'Charlie' };
cache.set(user3, { lastLogin: 'now' });
result.push(cache.has(user3));

user3 = null; // Removing the reference
// Garbage collector might run here in real situations

const user4 = { name: 'Charlie' }; // Same name, different object
result.push(cache.has(user4));

console.log(result);

function processData({ a = 10, b = 20 } = { a: 30 }) {
  console.log(a, b);
}

processData({ a: 5 });
processData();

const target = {
  secret: "hidden",
  reveal: "nothing"
};

const handler = {
  get: function(obj, prop, receiver) {
    if (prop === "secret") {
      return "revealed";
    }
    return Reflect.get(...arguments);
  }
};

const proxy = new Proxy(target, handler);

with (proxy) {
  console.log(secret);
  console.log(reveal);
}

const items = ['apple', 'banana', 'cherry', 'date'];  

const result = items
  .map(item => item.toUpperCase())
  .filter(item => item.length > 5)
  .reduce((acc, item, index) => {
    return acc + (index === 0 ? '' : '-') + item.slice(0, 3);
  }, '');

console.log(result);

const array = [1, 2, 3];
array[-1] = 0;

console.log(array.length);

const numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];

const result = numbers
  .filter(n => n % 2 === 0)
  .map(n => n * 2)
  .reduce((acc, curr, idx, arr) => {
    if (idx === arr.length - 1) {
      return (acc + curr) / arr.length;
    }
    return acc + curr;
  }, 0);

console.log(result);