[V3] Implement new Concept Exercise: sets

This issue describes how to implement the sets concept exercise for the JavaScript track.

Getting started

Please please please read the docs before starting. Posting PRs without reading these docs will be a lot more frustrating for you during the review cycle, and exhaust Exercism’s maintainers’ time. So, before diving into the implementation, please read up on the following documents:

• The features of v3.
• Rationale for v3.
• What are concept exercise and how they are structured?

Please also watch the following video:

• The Anatomy of a Concept Exercise.

Goal

This exercise aims to teach students how (and why) to use sets in JavaScript.

Learning objectives

• Know how to add and remove elements from a Set
• Know how to check whether a value is in a Set
• Understand how Set checks equality
• Know how to iterate over Set keys, values, and entries
• Know how to convert between Set and Array
• Know how to use Set to remove duplicate elements from an array
• Know how WeakSet differs from Set
• Understand when WeakSet might be preferable to Set

Out of scope

• Implementing common set operations like union and difference

Concepts

• sets

Prerequisites

• arrays
• array-destructuring
• equality

After

• Use cases for WeakSet
• Lookup performance of Set vs. Array

Help

If you have any questions while implementing the exercise, please post the questions as comments in this issue.

[kristinaborn]

@SleeplessByte I’d like to tackle this one 😃

[kristinaborn]

I’m back from the dead and finally working on this 😅

I think I’m going to opt not to address WeakSet in this exercise after all, unless folks feel strongly that I should. I believe that it’s not used commonly enough outside of library code to be valuable to students.