What is the difference between closures and global scope in JavaScript?

What is the difference between closures and global scope in JavaScript?

In JavaScript, global scope refers to variables that are accessible from anywhere in your code, while closures are functions that remember the environment in which they were created, allowing them to access variables from that scope even when called outside of it.

Can you give me an example of a closure?

Sure! Here's a simple example:

function outerFunction() {
    let outerVariable = 'I am outside!';
    function innerFunction() {
        console.log(outerVariable);
    }
    return innerFunction;
}

const myClosure = outerFunction();
myClosure(); // Outputs: I am outside!

In this example, innerFunction is a closure that retains access to outerVariable even after outerFunction has finished executing.

How do closures help with data privacy?

Closures help with data privacy by allowing you to create private variables that cannot be accessed from outside the function. Only the inner function can access these variables, which helps encapsulate and protect the data.

Are there any performance implications of using closures?

Yes, using closures can have performance implications, especially if they create many references to outer variables. This can lead to increased memory usage, as the outer scope cannot be garbage collected as long as the closure exists. It's important to use them judiciously.