crocks/Tuple/nmap.js

A collection of well known Algebraic Datatypes for your utter enjoyment.

/** @license ISC License (c) copyright 2018 original and current authors */
/** @author Karthik Iyengar (karthikiyengar) */

var curry = require('../core/curry')
var isFunction = require('../core/isFunction')
var isInteger = require('../core/isInteger')
var isSameType = require('../core/isSameType')
var Tuple = require('./index')

var validTuple = function (n, m) { return isSameType(Tuple(n), m); }

function runMap(m, fns) {
  var n = fns.length
  if (!validTuple(n, m)) {
    throw new TypeError(("nmap: " + n + "-Tuple required"))
  }

  fns.forEach(function (fn) {
    if (!isFunction(fn)) {
      throw new TypeError('nmap: Functions required for all arguments')
    }
  })

  return m.mapAll.apply(m, fns)
}

var withLength = function (n, fn) {
  return Object.defineProperty(fn, 'length', {
    value: n
  })
}

function nmap(n) {
  if (!(isInteger(n) && n >= 1)) {
    throw new TypeError('nmap: Integer required for first argument')
  }

  switch (n) {
  case 1:
    return function (a, m) { return runMap(m, [ a ]); }
  case 2:
    return function (a, b, m) { return runMap(m, [ a, b ]); }
  case 3:
    return function (a, b, c, m) { return runMap(m, [ a, b, c ]); }
  case 4:
    return function (a, b, c, d, m) { return runMap(m, [ a, b, c, d ]); }
  case 5:
    return function (a, b, c, d, e, m) { return runMap(m, [ a, b, c, d, e ]); }
  case 6:
    return function (a, b, c, d, e, f, m) { return runMap(m, [ a, b, c, d, e, f ]); }
  case 7:
    return function (a, b, c, d, e, f, g, m) { return runMap(m, [ a, b, c, d, e, f, g ]); }
  case 8:
    return function (a, b, c, d, e, f, g, h, m) { return runMap(m, [ a, b, c, d, e, f, g, h ]); }
  case 9:
    return function (a, b, c, d, e, f, g, h, i, m) { return runMap(m, [ a, b, c, d, e, f, g, h, i ]); }
  case 10:
    return function (a, b, c, d, e, f, g, h, i, j, m) { return runMap(m, [ a, b, c, d, e, f, g, h, i, j ]); }
  default:
    return withLength(n + 1, function() {
      var parts = [].slice.call(arguments)
      return runMap(parts[parts.length - 1], parts.slice(0, parts.length - 1))
    })
  }
}

module.exports =
  curry(nmap)