const {maxBy} = require('./_30s.js'); test('maxBy is a Function', () => { expect(maxBy).toBeInstanceOf(Function); }); test('Produces the right result with a function', () => { expect(maxBy([{ n: 4 }, { n: 2 }, { n: 8 }, { n: 6 }], o => o.n)).toBe(8); }); test('Produces the right result with a property name', () => { expect(maxBy([{ n: 4 }, { n: 2 }, { n: 8 }, { n: 6 }], 'n')).toBe(8); });