123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108
import { memoize } from './memoize'
test('memoize function without input arguments', () => {  const fn = () => 4  const memoized = memoize(fn)  expect(typeof memoized()).toBe('function')})
test('happy', () => {  let counter = 0
  const fn = ({ a, b, c }) => {    counter++
    return a + b - c  }  const memoized = memoize(fn)  expect(memoized({    a : 1,    c : 3,    b : 2,  })).toBe(0)  expect(counter).toBe(1)  expect(memoized({    c : 3,    a : 1,    b : 2,  })).toBe(0)  expect(counter).toBe(1)})
test('normal function', () => {  let counter = 0  const fn = (a, b) => {    counter++
    return a + b  }  const memoized = memoize(fn)  expect(memoized(1, 2)).toBe(3)  expect(memoized(1, 2)).toBe(3)  expect(memoized(1, 2)).toBe(3)  expect(counter).toBe(1)  expect(memoized(2, 2)).toBe(4)  expect(counter).toBe(2)  expect(memoized(1, 2)).toBe(3)  expect(counter).toBe(2)})
test('async function', async () => {  let counter = 0  const delay = ms =>    new Promise(resolve => {      setTimeout(resolve, ms)    })  const fn = async (    ms, a, b  ) => {    await delay(ms)    counter++
    return a + b  }
  const memoized = memoize(fn)  expect(await memoized(    100, 1, 2  )).toBe(3)  expect(await memoized(    100, 1, 2  )).toBe(3)  expect(await memoized(    100, 1, 2  )).toBe(3)  expect(counter).toBe(1)  expect(await memoized(    100, 2, 2  )).toBe(4)  expect(counter).toBe(2)  expect(await memoized(    100, 1, 2  )).toBe(3)  expect(counter).toBe(2)})
test('string as argument', () => {  let count = 0  const foo = 'foo'  const tester = memoize(n => {    count++
    return `${ n }bar`  })  tester(foo)  tester(foo)  tester(foo)
  expect(tester(foo)).toEqual('foobar')
  expect(count).toEqual(1)
  tester('baz')
  expect(tester('baz')).toEqual('bazbar')
  expect(count).toEqual(2)})