Note that in JS a Set remembers insertion order, while in other languages like Python, it is unordered.

Resources

Create

const x = new Set()

const x = new Set(["abc", "abc", 123, "def"])
// Set( [ 123, "abc", "def" ] )

Order is preserved and the duplicates from later are removed.

new Set([ 'a', 'b', 'a'])
// Set(2) { 'a', 'b' }

Update

x.add("abc")

x.delete("abc")

Check if present

x.has("abc")

Iterate

for (const item of mySet1) {
  console.log(item)
}

(new Set([ 'a', 'b', 'a'])).values()
// [Set Iterator] { 'a', 'b' }

Cast

Convert to array.

const mySet = new Set([ 'a', 'b', 'a'])

[...mySet]
// [ 'a', 'b' ]