What is the difference between closure and lexical scoping?

What is the difference between closure and lexical scoping?

Closure refers to a function that retains access to its lexical scope, even when the function is executed outside that scope. Lexical scoping, on the other hand, is the way variable scope is determined in a program based on the location of the variables within the nested function structure.

Can you give me an example of closure in JavaScript?

Sure! Here's a simple example:

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

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

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

What about lexical scoping? Can you explain that?

Lexical scoping means that the scope of a variable is determined by its location within the source code. For example, if you declare a variable inside a function, it cannot be accessed from outside that function. This is how JavaScript determines which variables are accessible in a given context.

How do closures help in JavaScript?

Closures are useful for data encapsulation, allowing you to create private variables and functions. They enable you to maintain state in an asynchronous environment, such as when using callbacks or promises.