isSubsetOfintermediateconst a = new Set([1, 2])
const b = new Set([1, 2, 3])
a.isSubsetOf(b) // β true
b.isSubsetOf(a) // β falseUse Set.isSubsetOf() to check whether every element of this set is also in another set.
setA.isSubsetOf(setB) returns true if all elements of A are in B.
Challenge: Verify that a subset returns true.