05_reduce.test.js

/*
 * REDUCE
 *
 * You can implement almost anything with reduce.
 * But how do you implement reduce?
 * TIP: Use your friend, recursion
*/

function reduce(arr, fn, initial) {
  // TODO - IMPLEMENT ME
}

/* =========== DON'T CHANGE THE CODE AFTER THIS LINE =============== */

test('reduces an array', () =>
  expect(reduce([1, 2, 3, 4, 5], (a, b) => a + b, 0)).toEqual(15))