Function memoize

src/utils/function.js:20–48

(fn, { hasher, limit } = {})

 * @return {function}                       Returns the memoized function
 */
export function memoize (fn, { hasher, limit } = {}) {
  limit = limit == null ? Number.POSITIVE_INFINITY : limit
  hasher = hasher == null ? JSON.stringify : hasher

  return function memoize () {
    if (typeof memoize.cache !== 'object') {
      memoize.cache = {
        values: new Map(),
        lru: lruQueue(limit || Number.POSITIVE_INFINITY)
      }
    }
    const args = []
    for (let i = 0; i < arguments.length; i++) {
      args[i] = arguments[i]
    }
    const hash = hasher(args)

    if (memoize.cache.values.has(hash)) {
      memoize.cache.lru.hit(hash)
      return memoize.cache.values.get(hash)
    }

    const newVal = fn.apply(fn, args)
    memoize.cache.values.set(hash, newVal)
    memoize.cache.values.delete(memoize.cache.lru.hit(hash))

    return newVal
  }
}

/**
 * Memoize a given function by caching all results and the arguments,