What Happens When You Reassign a Variable with Let in JavaScript?

Ever found yourself scratching your head over JavaScript’s behavior regarding variable reassignment? Especially when dealing with `let` declarations—trust me, you’re not alone! So, let’s break it down and make it straightforward, shall we?

Picture this: you’ve declared a variable using `let` and assigned it a value. Then, out of nowhere, you decide to change that value. What do you think happens when you run `console.log()`? If you guessed that it displays the current value of the variable, you hit the nail on the head! That’s right: after reassigning a variable declared with `let`, `console.log()` will output the most recent value. And isn't that just the kind of clarity you want while preparing for an exam? 

For example, imagine you create a variable like this:

javascript
let favoriteColor = "blue";
favoriteColor = "green";
console.log(favoriteColor);


What do you expect to see? That’s right—“green!” 

Now, let’s look at the other options to see how they stack up. If someone were to suggest that `console.log()` would output `undefined`, they’d be mistaken. Why? Because `undefined` would only pop up if you tried accessing a variable that hasn’t been assigned a value at all, not after a reassignment. 

What about a `ReferenceError`? That typically rears its head only when you’re trying to call a variable that doesn't exist in your scope. So, if you thought `console.log()` might lead to that, it’s time to hit the books for a bit more clarity! 

Lastly, claiming that it would output “the last assigned value only” might sound appealing, but that’s misleading. The point is, `console.log()` reflects any value assigned to that variable before it’s logged, hence showing us a fuller snapshot of its journey rather than just resting on one status. 

So, when tackling questions about variable declarations and reassignment in JavaScript, remember that clarity is paramount! Understanding how `let` works under the hood can be the difference between acing or stumbling through the Salesforce JavaScript Developer Exam. And all these little nuances? They’re the stepping stones to grasping the bigger picture! 

As you prep for your exam, keep this knowledge at your fingertips. The next time you encounter a `let` variable, you'll not only know what to expect but also feel more confident making those variable changes.  Happy coding!