What is variable hoisting in JavaScript?

What is variable hoisting in JavaScript?

Variable hoisting is a JavaScript mechanism where variable declarations are moved to the top of their containing scope during compilation.

Can you give me an example of variable hoisting?

Sure! For instance, if you declare a variable after using it, JavaScript will still recognize it as defined. Like this:

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

Why does it log 'undefined' instead of throwing an error?

It logs 'undefined' because the declaration var x; is hoisted to the top, but the assignment x = 5; remains in place.

Are there any differences in hoisting with let and const?

Yes, let and const are also hoisted, but they are not initialized. Accessing them before declaration results in a ReferenceError.