Memoize.test.js

import { memoize } from '../Memoize'
import { union } from './cacheTest'
import { fibonacci } from '../../Dynamic-Programming/FibonacciNumber'
import { factorial } from '../../Recursive/Factorial'
import LFUCache from '../LFUCache'

const multipleFactorials = (arr) => arr.map(factorial)

describe('Testing Memoize', () => {
  it('expects the fibonacci function to use the cache on the second call', () => {
    const memoFibonacci = memoize(fibonacci)

    expect(memoFibonacci(5)).toEqual(fibonacci(5))
    expect(memoFibonacci(5)).toEqual(5)
    expect(memoFibonacci(10)).toEqual(fibonacci(10))
    expect(memoFibonacci(10)).toEqual(55)
  })

  it('expects the factorial function to use the cache on the second call', () => {
    const memoFactorial = memoize(factorial)

    expect(memoFactorial(5)).toEqual(factorial(5))
    expect(memoFactorial(5)).toEqual(120)
    expect(memoFactorial(10)).toEqual(factorial(10))
    expect(memoFactorial(10)).toEqual(3628800)
  })

  it('expects the multipleFactorials function to use the cache on the second call', () => {
    const memoMultipleFactorials = memoize(multipleFactorials)
    const input = [2, 3, 4, 5]

    expect(memoMultipleFactorials(input)).toEqual([2, 6, 24, 120])
    expect(memoMultipleFactorials(input)).toEqual(multipleFactorials(input))
  })

  it('expects the multipleFactorials function to use the cache on the second call', () => {
    const memoMultipleFactorials = memoize(multipleFactorials)
    const input = [2, 3, 4, 5]

    expect(memoMultipleFactorials(input)).toEqual([2, 6, 24, 120])
    expect(memoMultipleFactorials(input)).toEqual(multipleFactorials(input))
  })

  it('expects the union function to use the cache on the second call', () => {
    const memoUnion = memoize(union)
    const inputs = [new Set([1, 2, 3]), new Set([4, 3, 2]), new Set([5, 3, 6])]

    expect(memoUnion(...inputs)).toEqual(new Set([1, 2, 3, 4, 5, 6]))
    expect(memoUnion(...inputs)).toEqual(union(...inputs))
  })

  it('Testing with explicit cache -> LFUCache', () => {
    const LFU = new LFUCache(2)

    const memoizeFibonacci = memoize(fibonacci, LFU) // added LFU cache explicitly
    const fibOfFiveHundred = memoizeFibonacci(500)
    const fibOfOneHundred = memoizeFibonacci(100)

    expect(memoizeFibonacci(500)).toBe(fibOfFiveHundred)
    expect(memoizeFibonacci(100)).toBe(fibOfOneHundred)

    expect(LFU.leastFrequency).toBe(2)
  })
})