Check if a set is a subset of another set

This function checks whether the first set is a subset of the second set.

JavaScript:

let isSubset = (set1, set2) => [...set1].every(val => set2.has(val));

// Example
console.log(isSubset(new Set([1, 2]), new Set([1, 2, 3, 4, 5]))); // true
console.log(isSubset(new Set(['a', 'b', 'c']), new Set(['a', 'b']))); // false

TypeScript:

let isSubset = (set1: Set, set2: Set): boolean => [...set1].every(val => set2.has(val));

// Example
console.log(isSubset(new Set([1, 2]), new Set([1, 2, 3, 4, 5]))); // true
console.log(isSubset(new Set(['a', 'b', 'c']), new Set(['a', 'b']))); // false