What is JavaScript hoisting? Can you give me some examples?

What is JavaScript hoisting? Can you give me some 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, you can use it before its declaration.

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, x is hoisted, so the first console.log outputs undefined.

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 because the function is hoisted.

Are there any differences with let and const?

Yes, let and const are not hoisted in the same way. They are hoisted but remain in a 'temporal dead zone' until their declaration is encountered. Accessing them before declaration results in a ReferenceError.