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JavaScript JavaScript Basics Working with Strings Combine and Manipulate Strings

Posted by Dorian Ellison
Dorian Ellison
1,367 Points

I get an error message cannot read property "`" of null. What does that mean?

var firstName = "Dorian"; var lastName = "Ellison"; var role = "developer"; var msg = firstName (" ") lastName : role;

app.js 
var firstName = "Dorian";
var lastName = "Ellison"; 
var role = "developer";
var msg = firstName (" ") lastName :  role;
Dorian Ellison
Dorian Ellison
1,367 Points

My cousin is a developer and gave me this as a solution:

${firstName} ${lastName}: ${role};

The challenge task accepts this as a correct response, however the videos did not cover characters such as "`", "$", or "{}". The videos also don't cover why that would work. Why wasn't it covered? Did I miss something?

2 Answers

Jennifer Nordell
seal-mask
STAFF
.a{fill-rule:evenodd;}techdegree
Jennifer Nordell
Treehouse Teacher
Jennifer Nordell
.a{fill-rule:evenodd;}techdegree
Jennifer Nordell
Treehouse Teacher

Hi there, Dorian Ellison! The backticks, dollar signs, and curly braces just haven't been covered yet. But they will be! Your friend's solution was valid assuming it had the backticks. It's called a "template literal" and you will be taking courses/workshops later that cover them. You just aren't there quite yet!

It would be impossible to cover everything all at once, but if you continue down the same path, you will get there :smiley:

You could have also solved this using normal concatenation.

This would have also worked:

let msg = firstName + " " + lastName + ": " + role;

Your attempt seems to be missing any + signs to perform the concatenation. Also, the colon and accompanying space would need to be enclosed in quotation marks to create a string literal.

Hope this helps! :sparkles:

Dorian Ellison
Dorian Ellison
1,367 Points
Dorian Ellison
Dorian Ellison
1,367 Points

wow you're right. It's very easy to miss 1 minor detail that makes the difference. Thank you. At first I had ":" + " ", but I see now that you can have the space and the colon within the same literal! Thank you.