What are the differences between lexical and block scope in JavaScript?

What are the differences between lexical and block scope in JavaScript?

Lexical scope refers to the visibility of variables based on their location in the source code, while block scope is limited to the block in which a variable is defined, such as within curly braces.

Can you give me an example of lexical scope?

Sure! In the following code, the variable 'outerVar' is accessible inside 'innerFunction' due to lexical scoping:

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

And what about block scope?

Block scope is created by curly braces. For example:

if (true) {
    let blockVar = 'I am inside a block!';
}
console.log(blockVar); // This will throw an error because blockVar is not accessible here.

So, can I use 'var' to create block scope?

No, 'var' does not create block scope. It is function-scoped, meaning it is accessible throughout the function it is defined in, not just within the block.