Method difference

src/lualib/Set.ts:194–200

* @returns a new Set containing all the elements in this Set which are not also in the argument.

(other: ReadonlySet<T>)

     * @returns a new Set containing all the elements in this Set which are not also in the argument.
     */
    public difference(other: ReadonlySet<T>): Set<T> {
        const result = new Set<T>(this);
        for (const item of other) {
            result.delete(item);
        }
        return result;
    }

    /**
     * @returns a new Set containing all the elements which are in either this Set or in the argument, but not in both.