const person = {
  name: "John",
  greet: function() {
    const getMessage = () => `Hello, ${this.name}`;
    return getMessage();
  }
};

console.log(person.greet());

function a() {
   console.log(arguments[0]);
}

a([1]);

const handler = {
  get(target, prop) {
    if (prop in target) {
      return target[prop] * 2;
    } else {
      return `Property ${prop} not found`;
    }
  },
  set(target, prop, value) {
    if (typeof value === 'number') {
      target[prop] = Math.round(value);
      return true;
    }
    return false;
  }
};

const obj = { a: 5, b: 10 };
const proxy = new Proxy(obj, handler);

proxy.c = 7.8;
proxy.d = "hello";

console.log(obj.c, proxy.a, proxy.x);

const numbers = [0,0,0];

let i = 0;
const result = numbers.reduce((acc, _) => {
  return ++acc;
}, i);

console.log(i, result);

const numbers = [1, 2, 3, 4, 5];

const result = numbers
  .map(n => n * 2)
  .filter(n => n > 5)
  .reduce((acc, n, index) => {
    acc.sum += n;
    acc.indices.push(index);
    return acc;
  }, { sum: 0, indices: [] });

console.log(result.sum);
console.log(result.indices);

console.log('Start');

setTimeout(() => {
  console.log('Timeout 1');
}, 0);

Promise.resolve().then(() => {
  console.log('Promise 1');
}).then(() => {
  console.log('Promise 2');
});

setTimeout(() => {
  console.log('Timeout 2');
}, 0);

console.log('End');

function createCounter() {
  let count = 0;
  return {
    increment() {
      count++;
      return count;
    },
    getCount() {
      return count;
    }
  };
}

const counter = createCounter();

console.log(counter.increment());
console.log(counter.getCount());
console.log(counter.increment());
console.log(counter.getCount());

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);

function processData(data) {
  try {
    if (!data) {
      throw new TypeError('Data is missing');
    }
    
    const result = data.process();
    return result;
  } catch (error) {
    console.log(error instanceof ReferenceError ? 1 :
               error instanceof TypeError ? 2 :
               error instanceof SyntaxError ? 3 : 4);
  }
}

processData(null);

function createCounter() {
  let count = 0;
  return {
    increment: () => ++count,
    decrement: () => --count,
    get: () => count
  };
}

const counter1 = createCounter();
const counter2 = createCounter();
counter1.increment();
counter1.increment();
counter2.increment();
console.log(counter1.get(), counter2.get());
const { increment, get } = counter1;
increment();
console.log(get());

const firstArrayData = [ 'JavaScript', 'Universe' ];
const secondArrayData = [ 'JavaScript', 'Universe' ];

console.log(firstArrayData == secondArrayData);
console.log(firstArrayData === secondArrayData);

const user = {
  name: 'Sarah',
  age: 25,
  getName() { return this.name; },
  getAge: () => this.age
};

const methods = {
  regular: user.getName,
  arrow: user.getAge
};

console.log(methods.regular());
console.log(methods.arrow());
console.log(user.getName());
console.log(user.getAge());

const numbers = [1, 2, 3, 4, 5];

const result = numbers
  .map(x => x * 2)
  .filter(x => x > 5)
  .reduce((acc, x) => {
    acc.push(x.toString());
    return acc;
  }, [])
  .map(x => x + '!')
  .join(' | ');

console.log(result);
console.log(typeof result);