memoizer using es6

memoizer.js

function memoizer (fn, initialState = null) {
  const _cache = initialState || {}

  return (...params) => {
    const _stringified = JSON.stringify(params)

    if (_cache[_stringified] === undefined) {
      const result = fn(...params)
      _cache[_stringified] = result
      return result
    }

    return _cache[_stringified]
  }
}