Welcome to the Treehouse Community

The Treehouse Community is a meeting place for developers, designers, and programmers of all backgrounds and skill levels to get support. Collaborate here on code errors or bugs that you need feedback on, or asking for an extra set of eyes on your latest project. Join thousands of Treehouse students and alumni in the community today. (Note: Only Treehouse students can comment or ask questions, but non-students are welcome to browse our conversations.)

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and a supportive community. Start your free trial today.

JavaScript Introducing ES2015 Objects and New Collection Types Map

What's the difference between set and add?

Hello, my question is in the title :) Thank you very much.

Ali Adams
Ali Adams
3,467 Points

The Add method adds a value to the end of the list. Set is used to replace an existing value in a specific index in the list. The usage of either depends on the program you're writing. So just be aware of what each one does and use it accordingly. Hope this helps.

2 Answers

set is the method you use to add a new key-value pair to a Map object.

add is the method you use to add a new unique value to a Set object.

Neither object has the other's method (Map doesn't have an add method, Set doesn't have a set method). It's just how they are named.

Couldn't agree more with Simmons Also, note that the add method in the Set prototype is what ensures the uniqueness of data