function delayedLog(item) {
  setTimeout(() => {
    console.log(item);
  }, 1000);
}
for (var i = 0; i < 3; i++) {
  delayedLog(i);
}

console.log(typeof null);
console.log(typeof function () {});
console.log(typeof {});
console.log(typeof 1);
console.log(typeof '');
console.log(typeof true);
console.log(typeof '{}');

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

const symbols = Object.getOwnPropertySymbols(obj);
const keys = Object.keys(obj);
const allProps = Reflect.ownKeys(obj);

console.log(symbols.length, keys.length, allProps.length);

function* generator() {
  yield 1;
  yield* [2, 3];
  yield* '4';
}

const gen = generator();
for (const value of gen) {
  console.log(value);
}

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

const counter1 = createCounter();
const counter2 = createCounter();

counter1();
counter1();
counter2();

const result = counter1() + counter2();
console.log(result);

const weakMap = new WeakMap();
const obj = {};
const gen = (function* () {
  yield 'value1';
  yield 'value2';
  yield* ['value1', 'value2']
})();

weakMap.set(obj, gen.next().value);

console.log(weakMap.get(obj));
console.log(gen.next().value);
console.log(gen.next().value);

const counter = (() => {
  let count = 0;
  
  return {
    increment() {
      count += 1;
      return this;
    },
    reset() {
      count = 0;
      return this;
    },
    get value() {
      return count;
    }
  };
})();

const { increment, value } = counter;

increment();
counter.increment();

console.log(value);

for (var i = 0; i < 3; i++) {
  const log = () => {
    console.log(i)
  }
  setTimeout(log, 1)
}

function recursiveBinarySearch(arr, target, start = 0, end = arr.length - 1) {
  if (start > end) {
    return -1;
  }

  const mid = Math.floor((start + end) / 2);

  if (arr[mid] === target) {
    return mid;
  } else if (arr[mid] < target) {
    return recursiveBinarySearch(arr, target, mid + 1, end);
  } else {
    return recursiveBinarySearch(arr, target, start, mid - 1);
  }
}

const result = recursiveBinarySearch([[[1, 2, 3, 4, 5, [6, 7], 8], 9], 6]);

console.log(result);

function processConfig(config) {
  const defaultPort = 8080;
  const defaultTimeout = 5000;
  
  const port = config?.port ?? defaultPort;
  const timeout = config?.timeout ?? defaultTimeout;
  const debug = config?.debug ?? false;
  
  return { 
    summary: `Port: ${port}, Timeout: ${timeout}, Debug: ${debug ? 'enabled' : 'disabled'}`,
    isUsingDefaults: port === defaultPort && timeout === defaultTimeout
  };
}

const result = processConfig({ port: 0, timeout: null });
console.log(result.summary);

function Car(make) {
  this.make = make;
}

function Truck(make) {
  this.make = make;
}

const car = new Car('Toyota');
const truck = new Truck('Toyota');
var newCar = car;

console.log(car.__proto__ === truck.__proto__);
console.log(car.constructor === truck.constructor);
console.log(car instanceof Truck);
console.log(truck instanceof Car);
console.log(Truck.prototype.isPrototypeOf(car));
console.log(Car.prototype.isPrototypeOf(truck));
console.log(truck === car);
console.log(newCar === car);

function processUserData(data) {
  const settings = {
    theme: data.preferences?.theme ?? 'light',
    notifications: data.preferences?.notifications ?? true,
    fontSize: data.preferences?.fontSize ?? 16
  };
  
  let status = data.status ?? 'active';
  let reputation = data.reputation ?? 0;
  
  console.log(reputation || 'No reputation yet');
  return settings;
}

processUserData({ status: '', reputation: 0 });

const value = { number: 100 };
function increment(obj) {
  obj.number++;
}
increment(value);
console.log(value.number);

type User = {
  id: number;
  name: string;
  email?: string;
};

function processUser<T extends User>(user: T): T & { processed: boolean } {
  return { ...user, processed: true };
}

const partialUser = { id: 1, name: 'Alice' };
const result = processUser(partialUser);

console.log(typeof result.email);

var a=[1], b=1, c="1", d={1:1}
console.log(Array.isArray(a)); 
console.log(Array.isArray(b)); 
console.log(Array.isArray(c)); 
console.log(Array.isArray([d])); 
console.log(Array.isArray([]));

const num1 = 9007199254740992n;
const num2 = 1n;

const result1 = num1 + num2;
const result2 = Number(num1) + Number(num2);
const result3 = num1 + BigInt(1);
const result4 = String(num1) + String(num2);

console.log(typeof result2 === typeof result1, result1 === result3, result4);

const arr = [1, 5, 10, 15];
console.log(arr.fill(0, 2, 0, 2, 0, 2, 1));

function createSymbolDemo() {
  const obj = {};
  
  const sym1 = Symbol('description');
  const sym2 = Symbol('description');
  const sym3 = Symbol.for('shared');
  const sym4 = Symbol.for('shared');
  
  obj[sym1] = 'Value 1';
  obj[sym2] = 'Value 2';
  obj[sym3] = 'Value 3';
  obj[sym4] = 'Value 4';
  
  console.log(Object.keys(obj).length, sym1 === sym2, sym3 === sym4, obj[sym3]);
}

createSymbolDemo();

const obj = {
  value: 011,
  increment() {
    this.value++;
  }
};

const increment = obj.increment;
increment();

console.log(obj.value);

function* generateSequence() {
  let i = 1;
  while (i <= 3) {
    yield i++;
  }
}

function* extendSequence() {
  yield* generateSequence();
  yield* [4, 5];
  yield 6;
}

const generator = extendSequence();
const result = [];

for (const value of generator) {
  if (value % 2 === 0) {
    result.push(value * 2);
  } else {
    result.push(value);
  }
}

console.log(result);

console.log(typeof Object);
console.log(typeof Object());
console.log(typeof 'Object');
console.log(typeof new Object);