function processConfig(config) {
  const defaults = {
    timeout: 1000,
    retries: 3,
    enabled: false,
    count: 0
  };
  
  const settings = {
    ...defaults,
    ...config
  };
  
  const effectiveTimeout = settings.timeout ?? 500;
  const effectiveRetries = settings.retries ?? 1;
  const effectiveEnabled = settings.enabled ?? true;
  const effectiveCount = settings.count ?? 5;
  
  console.log([effectiveTimeout, effectiveRetries, effectiveEnabled, effectiveCount]);
}

processConfig({ timeout: null, retries: 0, enabled: undefined });

let funcs = [];

for (var i = 0; i <= 3; i++) {
  funcs.push(() => i);
}

console.log(funcs[0]());
console.log(funcs[1]());
console.log(funcs[2]());

const numbers = [33, 2, 8];
numbers.sort();
console.log(numbers);

❓Что будет на выходе?

const x = "5";
const y = 3;
const result = x - y;
console.log(result);

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');