What are closures in JavaScript?

A closure is created when a function remembers variables from its lexical scope.

Example

example.js
Copy
function outer() {
  let count = 0;

  return function inner() {
    count++;

    console.log(count);
  };
}

const counter = outer();

counter();

counter();

Interview Tip

Closures are heavily used in:

• React
• Event handlers
• Callbacks
• Timers
• Data privacy