'use strict'

// function utils

/**

* Memoize a given function by caching the computed result.

* The cache of a memoized function can be cleared by deleting the `cache`

* property of the function.

*

* @param {function} fn The function to be memoized.

* Must be a pure function.

* @param {function(args: Array)} [hasher] A custom hash builder.

* Is JSON.stringify by default.

* @return {function} Returns the memoized function

*/

exports.memoize = function (fn, hasher) {

return function memoize () {

if (typeof memoize.cache !== 'object') {

memoize.cache = {}

}

const args = []

for (let i = 0; i < arguments.length; i++) {

args[i] = arguments[i]

}

const hash = hasher ? hasher(args) : JSON.stringify(args)

if (!(hash in memoize.cache)) {

memoize.cache[hash] = fn.apply(fn, args)

}

return memoize.cache[hash]

}

}

/**

* Find the maximum number of arguments expected by a typed function.

* @param {function} fn A typed function

* @return {number} Returns the maximum number of expected arguments.

* Returns -1 when no signatures where found on the function.

*/

exports.maxArgumentCount = function (fn) {

return Object.keys(fn.signatures || {})

.reduce(function (args, signature) {

const count = (signature.match(/,/g) || []).length + 1

return Math.max(args, count)

}, -1)

}

/**

* Call a typed function with the

* @param {function} fn A function or typed function

* @return {number} Returns the maximum number of expected arguments.

* Returns -1 when no signatures where found on the function.

*/

exports.callWithRightArgumentCount = function (fn, args, argCount) {

return Object.keys(fn.signatures || {})

.reduce(function (args, signature) {

const count = (signature.match(/,/g) || []).length + 1

return Math.max(args, count)

}, -1)

}