Truthy and falsy assignment

[6151richmondstreet]

I’m back with what is probably a boneheaded question. I’m reviewing the module on conditional statements (JavaScript is kicking my butt and I realized I needed to go back to the top of the unit and review what I’d learned because it just wasn’t sticking), and here’s what it says:

“Say you have a website and want to take a user’s username to make a personalized greeting. Sometimes, the user does not have an account, making the username variable falsy. The code below checks if username is defined and assigns a default string if it is not:”

And then the code that follows looks like this:

let username = ‘’;
let defaultName;

if (username) {
defaultName = username;
} else {
defaultName = ‘Stranger’;
}

console.log(defaultName); // Prints: Stranger

What’s perplexing me is how “let defaultName” is a complete idea. Is it because the variable is assigned later with “defaultName = ‘Stranger’;”? Or is prefacing it with “let” enough for me to speak defaultName into existence? Thanks in advance for any input you can offer.

[dcross_athlete]

let username = ‘’;

We initialize a username variable and assign it to an empty string, which is considered falsy.

let defaultName;

Then, we initialize a defaultName variable, which has the value undefined.
It’s ok to have the defaultName variable initialized as undefined, because later on…

if (username) {
defaultName = username;
} else {
defaultName = ‘Stranger’;
}

We’re assigning defaultName to username if username is truthy (if it isn’t an empty string).
Or we’re assigning defaultName to ‘Stranger’ if username is falsy (if it’s an empty string).

@6151richmondstreet

is prefacing it with “let” enough for me to speak defaultName into existence?

Yes, you can speak defaultName into existence as undefined by using just “let”.

[6151richmondstreet]

Thank you so much for breaking it down like that! I understand now.