Closures

A closure is a function that remembers and can access its lexical scope, even when the function is executed outside that scope.

Example

function outerFunction() {
    let outerVariable = "I'm outside!";

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

    return innerFunction;
}

const closure = outerFunction();
closure(); // Output: I'm outside!

Explanation: Here, innerFunction is a closure because it remembers the outerVariable from its lexical scope, even after outerFunction has finished executing.

Application: Closures are commonly used for data encapsulation and to create function factories.