variations.js

/* The MIT License (MIT) Copyright (c) 2016 David Szakallas */
/*
  Variate an object or array!
  
  Object:
  {
    bananas: [1, 2],
    apples: [3, 4]
  }
  will become:
  [
    { banana: 1, apple: 3 },
    { banana: 1, apple: 4 },
    { banana: 2, apple: 3 },
    { banana: 2, apple: 4 }
  ]

*/
'use strict'

const pluralize = require('pluralize')
const reduce = require('lodash.reduce')
const assign = require('lodash.assign')
const set_ = require('lodash.set')


function * iterate (value, key) {
  if (Array.isArray(value)) {
    const name = pluralize(key, 1)
    for (const item of value) {
      yield set_({}, `${name}`, item)
    }
  } else {
    yield set_({}, `${key}`, value)
  }
}

function variations (object) {
  return (reduce(object, (partials, value, key) => {
    return function * () {
      for (const partial of partials()) {
        for (const item of iterate(value, key)) {
          yield assign({}, partial, item)
        }
      }
    }
  }, function * () { yield { } }))()
}

module.exports = variations