1234567891011121314151617181920212223242526272829303132333435
import { reduce } from './reduce'
const reducer = (  prev, current, i) => {  expect(i).toBeNumber()
  return prev + current}const initialValue = 1const list = [ 1, 2, 3 ]
test('happy', () => {  expect(reduce(    reducer, initialValue, list  )).toEqual(7)})
test('with object as iterable', () => {  expect(() =>    reduce(      reducer, initialValue, {        a : 1,        b : 2,      }    )).toThrowWithMessage(TypeError, 'reduce: list must be array or iterable')})
test('with undefined as iterable', () => {  expect(() => reduce(    reducer, initialValue, undefined  )).toThrowWithMessage(TypeError,    'reduce: list must be array or iterable')})