const s1 = new Set() // empty
const s2 = new Set([1, 2, 3]) // from array
console.log(s2.size) // β 3Use the Set constructor to create a new set, optionally passing an iterable.
new Set([1,2,3]) creates a Set from an iterable.
Challenge: Verify that new Set([1,2,3]).size equals 3.