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');

let proto = { a: 1 };
let obj = Object.create(proto);

Object.defineProperty(obj, 'a', {
  value: 3,
  writable: true,
  enumerable: true,
  configurable: true
});

console.log(obj.a);
proto.a = 3;
console.log(obj.a);

const a = 9007199254740991n;
const b = 2n;

function performCalculation() {
  const c = a + 1n;
  const d = c / b;
  const e = d * 2n - 1n;
  
  const result = Number(e) === Number(a);
  console.log(result);
}

performCalculation();

const obj = {
  [Symbol('a')]: 'hidden',
  a: 'visible',
  [Symbol.for('b')]: 'registered',
  b: 123
};

const symbol1 = Symbol.for('b');
const symbol2 = Symbol.for('b');

console.log(obj.a + ', ' + 
  obj[Symbol('a')] + ', ' + 
  obj[symbol1] + ', ' + 
  (symbol1 === symbol2));

console.log(typeof null);
console.log(typeof undefined);
console.log(typeof {});
console.log(typeof []);

const num = 10;
const str = num.toString().padStart(0, "9");
console.log(str);

function* counter() {
  let i = 0;
  while (true) {
    const direction = yield i;
    if (direction === 'up') i += 2;
    else if (direction === 'down') i -= 1;
    else i += 1;
  }
}

const count = counter();
console.log(count.next().value);
console.log(count.next('up').value);
console.log(count.next('down').value);
console.log(count.next().value);

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());

function* genSequence() {
  const result = yield 'first';
  console.log(result);
  yield* [1, 2];
  return 'done';
}

const gen = genSequence();
let next = gen.next('ignored');
console.log(next.value);
next = gen.next('second');
next = gen.next();
console.log(next.value);
next = gen.next();
console.log(next);

function calc(num) {
   return num + 0.01 * '0';
}

typeof calc('hello');

function Animal(name) {
  this.name = name;
}

Animal.prototype.getName = function() {
  return this.name;
};

function Dog(name, breed) {
  Animal.call(this, name);
  this.breed = breed;
}

Dog.prototype = Object.create(Animal.prototype);
Dog.prototype.constructor = Dog;

Dog.prototype.getName = function() {
  return `Dog called ${Animal.prototype.getName.call(this)}`;
};

const myDog = new Dog('Rex', 'German Shepherd');
console.log(myDog.getName());

function asyncQuiz() {
  return new Promise((resolve) => {
    setTimeout(() => resolve('World'), 100);
  });
}

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

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

async function asyncArrayOperations() {
  const array1 = [1, 2, 3];
  const array2 = [4, 5, 6];
  const array3 = [7, 8, 9];

  const result = await Promise.all([array1, array2, array3].map(async arr => {
    return await arr.filter(async (acc, num) => {
      return (await acc) + num;
    }, Promise.resolve(0));
  }));

  console.log(result);
}

asyncArrayOperations();

console.log(new RegExp({}).test("test"));
console.log(new RegExp({}).test("why?"));
console.log(new RegExp({}).test("cause"));