Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

JavaScript Object-Oriented JavaScript Working with Classes in JavaScript Adding methods to classes

I don't quite understand what does 'String(this.gpa)' works here?

Also, why we don't need to add constructor(gpa, this.gpa)?

class Student {
        this.gpa = gpa;
  stringGPA() { 
    return String(this.gpa);

const student = new Student(3.9);

1 Answer

Hi Hanwen!

this.gpa = gpa;

Just makes the value passed to the class constructor a class/instance attribute/property and as such whenever you need to access it within the class instance you need to reference it with this.gpa.

"this" being that particular class instance.

The String() function just casts/converts the numeric value to a string.

More info:



I hope that helps.

Stay safe and happy coding!

Got it! Thank you, Peter