What is JavaScript hoisting and can you give me examples?

What is JavaScript hoisting and can you give me examples?

JavaScript hoisting is a behavior where variable and function declarations are moved to the top of their containing scope during compilation. For example, if you declare a variable using var, it can be used before its declaration in the code.

Can you show me a code example of hoisting with variables?

Sure! Here's an example:

console.log(x); // undefined
var x = 5;
console.log(x); // 5

In this case, the first console.log outputs undefined because the declaration of x is hoisted, but the assignment happens later.

What about function hoisting? Can you explain that?

Absolutely! Function declarations are also hoisted. For example:

hello(); // 'Hello!'
function hello() {
    console.log('Hello!');
}

Here, you can call hello() before its declaration, and it will work because the entire function is hoisted.

Are there any differences between var, let, and const in hoisting?

Yes, there are differences! var is hoisted and initialized to undefined, while let and const are hoisted but not initialized, leading to a ReferenceError if accessed before declaration.