text: const {differenceWith} = require('./_30s.js');
  
  test('differenceWith is a Function', () => {
    expect(differenceWith).toBeInstanceOf(Function);
  });
  test('Filters out all values from an array', () => {
    expect(
      differenceWith([1, 1.2, 1.5, 3, 0], [1.9, 3, 0], (a, b) => Math.round(a) === Math.round(b))
    ).toEqual([1, 1.2]);
  });
  