JavaScript? ??? ??? ??? ???????. ??? ?? ??? ???? ?? ???? ???? ?? ? ??? ?????. ???? ???? ?? ????? ??? ? ??? ?? ???? ?? ????? ??? ??? ??? ? ?? ???? ??? ????.

???? ?? ??? ???? ?? ??? ???? ?????? ??? ??? ???? ? ??? ???????.

???? ??????

????? ???? ??? ???? ??? “??”?? ?????. ?? ???? ?? ??? ??? ??? ??? ?? ??? ??? ???? ? ??? ?????. ??? ?? ????? ??? ???? ??? ??? ???? ???? ??? ? ????.

???? ?? ?? ??? ????.

function outerFunction() {
  let message = "Hello, Closure!";

  function innerFunction() {
    console.log(message);
  }

  return innerFunction;
}

const myClosure = outerFunction();
myClosure(); // Output: Hello, Closure!

? ??? innerFunction? ??????. externalFunction? ??? ?????? innerFunction? ??? ????? ??? ???? ? ????. ??? ??? ????. ???? ???? ?????!

???? ? ??????

???? ?? ???? ??? ????. ?? ??? ???? ? ??? ? ?? ???? ?????.

??? ??? ??? ??? ????.

• ???: ???? ???? ??? ??? ??? ??? ?? ? ????.
• ???: ??? ????? ???? ??? ????? ???? ? ??? ???.
• ???: ???? ?? ? ?? ??? ?? ??? ????? ??? ??? ???? ? ????.

???? ?? ??

?? ??? ??? ???? ? ?? ??? ????.

1. ???? ?? ??

JavaScript?? private ?? protected? ?? ???? ??? ???? ??? ???? ? ??? ??? ? ????.

function createCounter() {
  let count = 0;

  return {
    increment: function () {
      count++;
      console.log(count);
    },
    decrement: function () {
      count--;
      console.log(count);
    },
  };
}

const counter = createCounter();
counter.increment(); // Output: 1
counter.increment(); // Output: 2
counter.decrement(); // Output: 1

??? count? ?? ? ?? ??? ???? ???? ? ????. ? ???? ???? ?? ?????? ??? ???? ?????.

2. ?? ???

???? ???? ???? ??? ?? ??? ? ????.

function createMultiplier(multiplier) {
  return function (number) {
    return number * multiplier;
  };
}

const double = createMultiplier(2);
const triple = createMultiplier(3);
console.log(double(5)); // Output: 10
console.log(triple(5)); // Output: 15

???? ???? ?? ??? ?? ??? ??? ??? ????.

3. ??

???? ??? ?? ?? ?? ??? ??? ???? ??? ????? ??? ??????? ?? ?????.

function memoize(fn) {
  const cache = {};

  return function (key) {
    if (cache[key]) {
      console.log("Fetching from cache:", key);
      return cache[key];
    }
    console.log("Calculating result:", key);
    const result = fn(key);
    cache[key] = result;
    return result;
  };
}

const square = memoize((x) => x * x);
console.log(square(4)); // Calculating result: 4 => Output: 16
console.log(square(4)); // Fetching from cache: 4 => Output: 16

??????? ???? ???? ??? ??? ??? ?????? ?? ?? ??? ????.

4. ??? ???

???? ??? ???? ????? ??? ???? ?? ?? ?????.

function setupButton(id) {
  let clickCount = 0;

  document.getElementById(id).addEventListener("click", function () {
    clickCount++;
    console.log(`Button clicked ${clickCount} times`);
  });
}
setupButton("myButton");

??? ??? ??? ??? ???? ???? ???? ?? ?? ???? ??? ??? ? ?? ??? ?????.

???? ??? ?? ??? ??

???? ?? ????? ???? ???? ??? ??? ??? ? ????.

• ???? ?? ??? ??: ? ??? ?? ??? ????? ???? ???? ?? ??? ??? ??? ? ????. Chrome DevTools? ?? ??? ???? ??? ???? ?????.
• ?? ??: ???? ???? ???? ??? ??? ? ???? ? ????. ???? ???? ?? ???? ?????.

??

???? JavaScript? ???? ??? ?????. ??? ??? ????? ???? JavaScript ??? ????? ???? ??? ???? ???? ?????.

???? ????? ??? ??, ??, ??? ?? ??? ??? ?? ????? ?? ???? ???? ??? ??? ? ????. ?? UI? ???? ??? ????? ???? ???? ???? ? ?????.

??? ?? ???? ??? ?? ??? ?????? ?? ??? ???!

? ??? JavaScript ???? ?? ?? ?????. ??? ??? PHP ??? ????? ?? ?? ??? ?????!