Source code for `Choose Functional` article

choose-functional-source-code.js

import getData from './data.js'

/*
 * Sum.
 * sum :: (Number, Number) → Number
 * 
 * Provided two numbers, return their summation.
 **/
const sum = (numX, numY) => numX + numY

/*
 * Increment.
 * incr :: Number → Number
 * 
 * Provided a number, return its value incremented by one.
 **/
const incr = num => sum(num, 1)

/*
 * Construct bins.
 * consBins :: Object → [[Number]]
 * 
 * Configuration parameters:
 * min - The numerical floor from which to initialize the first interval.
 * max - The numerical ceiling by which we limit the last of intervals.
 * width - The range encompassed by each interval.
 **/
const consBins = ({min = 0, max = Infinity, width = 1, accum = []}) =>
  // Ensure `max` does not exceed the range of our current interval...
  sum(min, width) > max
    ? // If so, return our accumulator;
      accum
    : // Otherwise, call upon our method recursively until we fulfill our
      // predicating condition.
      consBins({
        // Increment interval, so as to preclude overlap.
        min: incr(sum(min, width)),
        // `max` and `width` remain constant.
        max,
        width,
        // Wax upon our accumulator, combining it with a new array, in which the
        // current interval is represented.
        accum: accum.concat([[min, sum(min, width)]]),
      })

/*
 * Filter property by minimum and maximum values.
 * filterPropByMinMax :: Object → Array
 * 
 * From a collection, return only those cases where the given property falls
 * within range of specified minimum and maximum values.
 *
 * Configuration parameters:
 * {String} key - The property to -- and by which to -- filter.
 * {String} min - The minimum value by which to filter our attribute.
 * {String} min - The maximum value by which to filter our attribute.
 **/
const filterPropByMinMax = (arr, {key = '', min = '0', max = '100'}) =>
  arr.filter(
    // The numerical values encompassed by our JSON list assume the form of
    // strings; hence, we need abstract their numerical values via `parseInt`.
    // Our callback will return `true` provided the item's value is greater than
    // or equal to our minimum _and_ less than or equal to our maximum.
    item => parseInt(item[key], 10) >= min && parseInt(item[key], 10) <= max
  )

/*
 * Construct histogram object.
 * consHistObj :: (Array, [[Number]]) → String → Object
 **/
const consHistObj = (arr = [], bins = []) => (key = '') =>
  // For each of the nested arrays within out `bins` list...
  bins.reduce(
    (accum, currVal) => ({
      // Build upon our accumulator, which we initialize as an empty object...
      ...accum,
      // And where each entry is an object, whereof the the key shall represent
      // the minimum and maximum values encompassed by each bin (e.g., `15,19`),
      // and whereof the value shall delineate all vehicles encompassed by such
      // bin. We retrieve such values by of `filterPropByMinMax`...
      [currVal]: filterPropByMinMax(arr, {
        key,
        min: currVal[0],
        max: currVal[1],
        // And we calculate a total by way of `Array.prototype.length`.
      }).length,
    }),
    {}
  )

/*
 * Construct histogram object provided bins.
 * consHistObjWithBins :: (Object → [Object] → String) → Object
 * 
 * Configuration parameters:
 * {Number} min - The minimum value by which to filter our attribute.
 * {Number} min - The maximum value by which to filter our attribute.
 * {Number} width - The range encompassed by each interval.
 **/
const consHistObjWithBins = (arr = [], {min = 0, max = 100, width = 1}) => (
  key = ''
) => consHistObj(arr, consBins({min, max, width}))(key)

/*
 * Construct mileage histogram.
 **/
const consMileageHist = (key = '') =>
  consHistObjWithBins(getData(), {min: 0, max: 50, width: 4})(key)

// Apply our helper function, specifying in each case the relevant keys.
const consCityMileageHist = () => consMileageHist('cityFuelEfficiency')
const consHighwayMileageHist = () => consMileageHist('highwayFuelEfficiency')

// Initialize the app
console.log('City mileage', consCityMileageHist())
console.log('Highway mileage', consHighwayMileageHist())

choose-functional-source-json.js

const getData = () => [
  {
    accountId: 'ricartpreowned',
    bodyStyle: 'SUV',
    certified: 'true',
    cityFuelEfficiency: '19',
    driveLine: 'FWD',
    engine: 'V-6 cyl',
    exteriorColor: 'Crystal Black Pearl',
    features: [],
    fuelType: 'Premium Unleaded',
    highwayFuelEfficiency: '27',
    interiorColor: 'Graystone',
    internetPrice: '36500',
    inventoryType: 'all',
    make: 'Acura',
    model: 'MDX',
    modelCode: null,
    modelYear: '2016',
    msrp: '39975',
    newOrUsed: 'used',
    odometer: '15683',
    optionCodes: null,
    packages: [],
    status: 'Live',
    stockNumber: 'PRT26599',
    transmission: '9-Speed Automatic',
    trim: '3.5L',
    uuid: '76e6301d0a0e0ae757ee4a8214e64e3e',
    vin: '5FRYD3H27GB003986',
  },
  {
    accountId: 'ricartpreowned',
    bodyStyle: 'SUV',
    certified: 'true',
    cityFuelEfficiency: '19',
    driveLine: 'AWD',
    engine: 'V-6 cyl',
    exteriorColor: 'Kona Coffee',
    features: [],
    fuelType: 'Premium Unleaded',
    highwayFuelEfficiency: '27',
    interiorColor: 'Parchment',
    internetPrice: '23200',
    inventoryType: 'all',
    make: 'Acura',
    model: 'RDX',
    modelCode: 'TB4H3FJNW',
    modelYear: '2015',
    msrp: '26975',
    newOrUsed: 'used',
    odometer: '41042',
    optionCodes: null,
    packages: [],
    status: 'Live',
    stockNumber: 'PRT26325',
    transmission: '6-Speed Automatic',
    trim: 'Base',
    uuid: 'd39bb6200a0e0ae965f9dd8451a9d3c0',
    vin: '5J8TB4H34FL014179',
  },
  {
    accountId: 'ricartpreowned',
    bodyStyle: 'Sedan',
    certified: 'true',
    cityFuelEfficiency: '20',
    driveLine: 'Front-wheel Drive',
    engine: 'V-6 cyl',
    exteriorColor: 'Forged Silver Metallic',
    features: [],
    fuelType: 'Premium Unleaded',
    highwayFuelEfficiency: '31',
    interiorColor: 'Ebony',
    internetPrice: '25000',
    inventoryType: 'all',
    make: 'Acura',
    model: 'RLX',
    modelCode: 'KC1F9EKNW',
    modelYear: '2014',
    msrp: '29975',
    newOrUsed: 'used',
    odometer: '24145',
    optionCodes: null,
    packages: [],
    status: 'Live',
    stockNumber: 'PRC30840',
    transmission: '6-Speed Automatic',
    trim: 'Base',
    uuid: 'a950c22f0a0e0ae7682674b86f74b2f9',
    vin: 'JH4KC1F90EC000290',
  },
  {
    accountId: 'ricartpreowned',
    bodyStyle: 'Sedan',
    certified: 'true',
    cityFuelEfficiency: '24',
    driveLine: 'FWD',
    engine: 'I-4 cyl',
    exteriorColor: 'Fathom Blue Pearl',
    features: [],
    fuelType: 'Premium Unleaded',
    highwayFuelEfficiency: '35',
    interiorColor: 'Graystone',
    internetPrice: '22189',
    inventoryType: 'all',
    make: 'Acura',
    model: 'TLX',
    modelCode: 'UB1F3FJW',
    modelYear: '2015',
    msrp: '25975',
    newOrUsed: 'used',
    odometer: '10740',
    optionCodes: null,
    packages: [],
    status: 'Live',
    stockNumber: 'PRC30880',
    transmission: '8-Speed Dual-Clutch',
    trim: '2.4L',
    uuid: 'b39c6df10a0e0ae965f9dd8410212be7',
    vin: '19UUB1F35FA003225',
  },
  {
    accountId: 'ricartpreowned',
    bodyStyle: 'Sedan',
    certified: 'true',
    cityFuelEfficiency: '21',
    driveLine: 'AWD',
    engine: 'V-6 cyl',
    exteriorColor: 'Basque Red Pearl II',
    features: [],
    fuelType: 'Premium Unleaded',
    highwayFuelEfficiency: '31',
    interiorColor: 'Parchment',
    internetPrice: '22959',
    inventoryType: 'all',
    make: 'Acura',
    model: 'TLX',
    modelCode: 'UB3F5FKNW',
    modelYear: '2015',
    msrp: '26475',
    newOrUsed: 'used',
    odometer: '48819',
    optionCodes: null,
    packages: [],
    status: 'Live',
    stockNumber: 'PRC30720',
    transmission: '9-Speed Automatic',
    trim: '3.5L V6',
    uuid: '428c29ec0a0e0adf5dc3189615a52f77',
    vin: '19UUB3F55FA002184',
  },
  {
    accountId: 'ricartpreowned',
    bodyStyle: 'Sedan',
    certified: 'true',
    cityFuelEfficiency: '25',
    driveLine: 'FrontTrak',
    engine: 'TFSI four-cylinder engine',
    exteriorColor: 'Moonlight blue metallic',
    features: [],
    fuelType: 'Gas',
    highwayFuelEfficiency: '33',
    interiorColor: 'Nougat brown / Black',
    internetPrice: '25800',
    inventoryType: 'all',
    make: 'Audi',
    model: 'A4',
    modelCode: '8W25NG',
    modelYear: '2017',
    msrp: '31475',
    newOrUsed: 'used',
    odometer: '26873',
    optionCodes: null,
    packages: [],
    status: 'Live',
    stockNumber: 'PRC30907',
    transmission: '7-Speed Automatic S tronic',
    trim: '2.0T Premium',
    uuid: 'c835333a0a0e0aea4a9cbb01accadf43',
    vin: 'WAUGNAF45HN015721',
  },
  {
    accountId: 'ricartpreowned',
    bodyStyle: 'Sedan',
    certified: 'false',
    cityFuelEfficiency: '18',
    driveLine: 'quattro',
    engine: 'V-6 cyl',
    exteriorColor: 'Brilliant Black',
    features: [],
    fuelType: 'Premium Unleaded',
    highwayFuelEfficiency: '26',
    interiorColor: 'Amaretto/Black',
    internetPrice: '14399',
    inventoryType: 'all',
    make: 'Audi',
    model: 'A6',
    modelCode: '4F25VL',
    modelYear: '2010',
    msrp: '15475',
    newOrUsed: 'used',
    odometer: '86220',
    optionCodes: null,
    packages: [],
    status: 'Live',
    stockNumber: 'PRC31210',
    transmission: '6-Speed Automatic with Tiptronic',
    trim: '3.0 Premium',
    uuid: 'a6cbc0390a0e0ae804ee321d0ee3786f',
    vin: 'WAUFGAFBXAN050040',
  },
  {
    accountId: 'ricartpreowned',
    bodyStyle: 'SUV',
    certified: 'false',
    cityFuelEfficiency: '20',
    driveLine: 'quattro',
    engine: 'TFSI four-cylinder engine',
    exteriorColor: 'Brilliant black',
    features: [],
    fuelType: 'Gas',
    highwayFuelEfficiency: '28',
    interiorColor: 'Black',
    internetPrice: '0',
    inventoryType: 'all',
    make: 'Audi',
    model: 'Q5',
    modelCode: '8RB52A',
    modelYear: '2014',
    msrp: '0',
    newOrUsed: 'used',
    odometer: '37245',
    optionCodes: null,
    packages: [],
    status: 'Live',
    stockNumber: 'PRT26697',
    transmission: '8-Speed Automatic',
    trim: '2.0T Premium',
    uuid: 'c48ceb640a0e0a1748743f969666e5d0',
    vin: 'WA1CFAFP4EA087547',
  },
  {
    accountId: 'ricartpreowned',
    bodyStyle: 'Sedan',
    certified: 'true',
    cityFuelEfficiency: '23',
    driveLine: 'RWD',
    engine: 'I-4 cyl',
    exteriorColor: 'Black Sapphire Metallic',
    features: [],
    fuelType: 'Premium Unleaded',
    highwayFuelEfficiency: '35',
    interiorColor: 'Black',
    internetPrice: '26200',
    inventoryType: 'all',
    make: 'BMW',
    model: '328i',
    modelCode: '163O',
    modelYear: '2016',
    msrp: '32975',
    newOrUsed: 'used',
    odometer: '28587',
    optionCodes: null,
    packages: [],
    status: 'Live',
    stockNumber: 'PRC30904',
    transmission: '8-Speed Automatic',
    trim: '328i',
    uuid: 'c83531820a0d04fe7162913b9a1b8bf8',
    vin: 'WBA8E9C53GK646953',
  },
  {
    accountId: 'ricartpreowned',
    bodyStyle: 'Sedan',
    certified: 'false',
    cityFuelEfficiency: '22',
    driveLine: 'AWD',
    engine: 'I-4 cyl',
    exteriorColor: 'Brown',
    features: [],
    fuelType: 'Premium Unleaded',
    highwayFuelEfficiency: '33',
    interiorColor: null,
    internetPrice: '0',
    inventoryType: 'all',
    make: 'BMW',
    model: '528i xDrive',
    modelCode: '145B',
    modelYear: '2014',
    msrp: '0',
    newOrUsed: 'used',
    odometer: '31490',
    optionCodes: null,
    packages: [],
    status: 'Live',
    stockNumber: 'PRC31261',
    transmission: '8-Speed Automatic',
    trim: '528i Xdrive',
    uuid: 'c48ce9870a0d0cc73abae2a8e4367247',
    vin: 'WBA5A7C57ED620375',
  },
  {
    accountId: 'ricartpreowned',
    bodyStyle: 'Sedan',
    certified: 'true',
    cityFuelEfficiency: '22',
    driveLine: 'AWD',
    engine: 'I-4 cyl',
    exteriorColor: 'Dark Graphite II',
    features: [],
    fuelType: 'Premium Unleaded',
    highwayFuelEfficiency: '32',
    interiorColor: 'Black',
    internetPrice: '17000',
    inventoryType: 'all',
    make: 'BMW',
    model: '528i xDrive',
    modelCode: '125B',
    modelYear: '2012',
    msrp: '21975',
    newOrUsed: 'used',
    odometer: '54065',
    optionCodes: null,
    packages: [],
    status: 'Live',
    stockNumber: 'PRT25876A',
    transmission: '8-Speed Automatic',
    trim: '528i Xdrive',
    uuid: '160531990a0d0c1477af376f5345886f',
    vin: 'WBAXH5C59CDW05768',
  },
  {
    accountId: 'ricartpreowned',
    bodyStyle: 'SUV',
    certified: 'true',
    cityFuelEfficiency: '21',
    driveLine: 'AWD',
    engine: 'I-4 cyl',
    exteriorColor: 'Alpine White',
    features: [],
    fuelType: 'Premium Unleaded',
    highwayFuelEfficiency: '28',
    interiorColor: 'Black',
    internetPrice: '23997',
    inventoryType: 'all',
    make: 'BMW',
    model: 'X3 xDrive28i',
    modelCode: '14XD',
    modelYear: '2014',
    msrp: '26975',
    newOrUsed: 'used',
    odometer: '53864',
    optionCodes: null,
    packages: [],
    status: 'Live',
    stockNumber: 'PRT26245',
    transmission: '8-Speed Automatic Steptronic',
    trim: 'Xdrive28i',
    uuid: 'ae776bb60a0d0cc742fbd3bf8085527e',
    vin: '5UXWX9C57E0D27716',
  },
  {
    accountId: 'ricartpreowned',
    bodyStyle: 'SUV',
    certified: 'true',
    cityFuelEfficiency: '15',
    driveLine: 'AWD',
    engine: 'V-6 cyl',
    exteriorColor: 'Crimson Red Tintcoat',
    features: [],
    fuelType: 'Regular Unleaded',
    highwayFuelEfficiency: '22',
    interiorColor: 'Ebony',
    internetPrice: '32499',
    inventoryType: 'all',
    make: 'Buick',
    model: 'Enclave',
    modelCode: '4V14526',
    modelYear: '2016',
    msrp: '34475',
    newOrUsed: 'used',
    odometer: '17205',
    optionCodes: null,
    packages: [],
    status: 'Live',
    stockNumber: 'HTH1673A',
    transmission: '6-Speed Automatic Electronic with Overdrive',
    trim: 'Leather Group',
    uuid: 'bf6c580c0a0e0ae70e749f9f3f9ca075',
    vin: '5GAKVBKD4GJ260011',
  },
  {
    accountId: 'ricartpreowned',
    bodyStyle: 'SUV',
    certified: 'true',
    cityFuelEfficiency: '16',
    driveLine: 'AWD',
    engine: 'V-6 cyl',
    exteriorColor: 'Iridium',
    features: [],
    fuelType: 'Regular Unleaded',
    highwayFuelEfficiency: '22',
    interiorColor: 'Ebony',
    internetPrice: '25000',
    inventoryType: 'all',
    make: 'Buick',
    model: 'Enclave',
    modelCode: '4V14526',
    modelYear: '2015',
    msrp: '27975',
    newOrUsed: 'used',
    odometer: '49983',
    optionCodes: null,
    packages: [],
    status: 'Live',
    stockNumber: 'PRT26636',
    transmission: '6-Speed Automatic Electronic with Overdrive',
    trim: 'Leather Group',
    uuid: '87a7a8a50a0e0ae8145e712d37eb13c1',
    vin: '5GAKVBKD3FJ171464',
  },
  {
    accountId: 'ricartpreowned',
    bodyStyle: 'SUV',
    certified: 'true',
    cityFuelEfficiency: '16',
    driveLine: 'AWD',
    engine: 'V-6 cyl',
    exteriorColor: 'Carbon Black Metallic',
    features: [],
    fuelType: 'Regular Unleaded',
    highwayFuelEfficiency: '22',
    interiorColor: 'Choccahino',
    internetPrice: '24300',
    inventoryType: 'all',
    make: 'Buick',
    model: 'Enclave',
    modelCode: '4V14526',
    modelYear: '2014',
    msrp: '29475',
    newOrUsed: 'used',
    odometer: '44320',
    optionCodes: null,
    packages: [],
    status: 'Live',
    stockNumber: 'PRT26346',
    transmission: '6-Speed Automatic',
    trim: 'Leather Group',
    uuid: 'e30ceceb0a0e0a6b13730521e203a86b',
    vin: '5GAKVBKD8EJ273762',
  },
  {
    accountId: 'ricartpreowned',
    bodyStyle: 'SUV',
    certified: 'true',
    cityFuelEfficiency: '16',
    driveLine: 'AWD',
    engine: 'V-6 cyl',
    exteriorColor: 'Atlantis Blue Metallic',
    features: [],
    fuelType: 'Regular Unleaded',
    highwayFuelEfficiency: '22',
    interiorColor: 'Ebony',
    internetPrice: '25000',
    inventoryType: 'all',
    make: 'Buick',
    model: 'Enclave',
    modelCode: '4V14526',
    modelYear: '2014',
    msrp: '29725',
    newOrUsed: 'used',
    odometer: '33709',
    optionCodes: null,
    packages: [],
    status: 'Live',
    stockNumber: 'PRT26012',
    transmission: '6-Speed Automatic',
    trim: 'Leather Group',
    uuid: '2d5201e20a0e0aea4a9cbb0140681074',
    vin: '5GAKVBKD2EJ239865',
  },
]

export default getData