Set in JavaScript

A Set in JavaScript keeps track of values and only stores unique values.

const arr = [0,1,1,1,2,3]
const set = new Set([...arr])
console.log(set)

Sets are great to keep track of active Filter Badges or of loading / fetching states when making requests to external data sources.

Methods

add()

Adds an entry in a Set and takes the entry as argument

delete()

Removes a specified entry from the Set

has()

Returns a boolean depending on the value existing or not in the Set

Questions

• How can you get the size / length of a set?
  .size property returns the amount of unique elements of each Set.
• How is the performance compared to an array?

Terms

References