js浏览器私有写法

function createCounter() {
  let count = 0; // 私有变量

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

const counter = createCounter();
console.log(counter.increment()); // 1
console.log(counter.increment()); // 2
console.log(counter.decrement()); // 1

class Counter {
  #count = 0; // 私有字段

  increment() {
    this.#count++;
    return this.#count;
  }

  decrement() {
    this.#count--;
    return this.#count;
  }
}

const counter = new Counter();
console.log(counter.increment()); // 1
console.log(counter.increment()); // 2
console.log(counter.decrement()); // 1

function createClosure() {
  let largeData = new Array(1000000).fill('some data');

  return function() {
    console.log(largeData);
  };
}

const closure = createClosure();
closure(); // 使用闭包

// 解除引用
largeData = null;