isSupersetOf < Set < JavaScript

New, not-widely-supported method 1/24. The isSupersetOf() method of a Set takes a set and returns a boolean indicating if all elements of the given set are in this set.

    
    const evens = new Set([2, 4, 6, 8, 10, 12, 14, 16, 18]);

    const fours = new Set([4, 8, 12, 16]);

    const evensSuperSetOfFours = evens.isSupersetOf(fours);

    console.log(evensSuperSetOfFours);
    // true