JavaScriptEasy

How can closures be used to create private variables?

By FrontendPro Editorial Team Updated 8/8/2026

#JavaScript

Answer

Closures in JavaScript can be used to create private variables by defining a function within another function. The inner function has access to the outer function's variables, but those variables are not accessible from outside the outer function. This allows you to encapsulate and protect the variables from being accessed or modified directly.

function createCounter() {
  let count = 0; // private variable

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

const counter = createCounter();
console.log(counter.increment()); // 1
console.log(counter.getCount()); // 1
console.log(counter.count); // undefined