How can I use closures to create private variables in JavaScript?
Asked on Oct 07, 2025
Answer
Closures in JavaScript allow you to create private variables by defining a function within another function, where the inner function has access to the outer function's scope. This technique is often used to encapsulate data and restrict access from the outside.
<!-- BEGIN COPY / PASTE -->
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.increment()); // 2
console.log(counter.decrement()); // 1
console.log(counter.getCount()); // 1
<!-- END COPY / PASTE -->Additional Comment:
✅ Answered with JavaScript best practices.- The "createCounter" function defines a private variable "count" that is not accessible directly from outside.
- The returned object contains methods that form closures over the "count" variable, allowing controlled access and modification.
- Each call to "createCounter" creates a new closure with its own private "count" variable.
- This pattern is useful for encapsulating state and behavior in a controlled manner.
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