const promisify = require('js-flock').promisify;
  const readFile = require("fs").readFile;

  const readFileAsync = promisify(readFile); // Promise version of read file

  // Native version of read file
  readFile('test.txt', 'utf8', (err, data) => {
    if (err) {
      return console.log(err);
    }
    console.log(data);
  });

  // Promisify version
  readFileAsync('test.txt', 'utf8')
    .then((data) => console.log(data))
    .catch((err) => console.log(err));

  const fun = (cb) => cb(undefined, 'res1', 'res2');
  const funAsync = promisify(fun, { multiArgs: true });

  funAsync().then(([r1, r2]) => {
    // r1 - res1
    // r2 - res2
  });

  const collar = require('js-flock').collar;

  const MAX_WAIT_TIME = 500;

  // Http request will be rejected if it's not resolved in 0.5 seconds
  collar(Http.get('test-url'), MAX_WAIT_TIME)
    .then((response) => console.log(response))
    .catch((err) => console.log('promise have timed out'));

  // Collar will reject promise chain as one of promises are not resolved in max time
  collar(Promise.all([
    new Promise((resolve) => setTimeout(resolve, 50, '1')),
    new Promise((resolve) => setTimeout(resolve, 1000, '2'))
  ]), MAX_WAIT_TIME)
  .then(() => { /* not called as second promise have timed out */  })
  .catch((err) => { // CollarError = { isStrangled: true, message: 'Promises have timed out' }
    if (typeof err === 'object' && err.isStrangled) {
      console.log(err.message); // 'Promises have timed out'
    }
  });

  const toEnum = require('js-flock').toEnum;

  const vehicleType = toEnum({
    CAR: 'C',
    TRUCK: 'T',
    AIRPLANE: 'A',
    HELICOPTER: 'H',
    canFly(type) { // Define custom helper
      return type === this.AIRPLANE || type === this.HELICOPTER;
    }
  });

  const vehicle = getVehicle();

  if (vehicle.type === vehicleType.TRUCK) {
    // Special behaviour only for truck vehicles
  }

  if (vehicleType.canFly(vehicle.type)) {
    // Special behaviour for vehicles that can fly
  }

  // enum is immutable
  vehicleType.TRUCK = 'boat'; // vehicleType.TRUCK === 'T'

  // Each enum have standard helpers

  vehicleType.keys(); // ['CAR', 'TRUCK', 'AIRPLANE', 'HELICOPTER'] - helper functions are not included in keys
  vehicleType.values(); // ['C', 'T', 'A', 'H']

  vehicleType.exists('C'); // true
  vehicleType.exists('something'); // false

  vehicleType.haveKey('CAR'); // true
  vehicleType.haveKey('something'); // false


  // When keys are equal to values we can use short notation to define enum

  const gender = toEnum(['MAN', 'WOMEN', 'OTHER']);

  // The above is same as writing

  const gender = toEnum({
    MAN: 'MAN',
    WOMEN: 'WOMEN',
    OTHER: 'OTHER'
  });

  const sort = require('js-flock').sort;

  sort([1,4,2]).asc(); // sort array in ascending order [1, 2, 4]
  sort([1,4,2]).desc(); // sort array in descending order [4, 2, 1]

  // Sort persons (array of objects) ascending by lowercase names
  sort(persons).asc((p) => p.name.toLowerCase());

  // There is no exception if we try to sort values that are not sortable
  // If input is not array same value is returned back
  sort(null).asc(); // return null
  sort(33).desc(); // return 33

  sort(persons).asc((p) => p.name.toLowerCase());

  // Above statement is equivalent to

  persons.sort((a, b) => {
    // == null are true for undefined and null.
    // We need to check that first in order to move undefined/null values to bottom of list
    if (a.name == null) return 1;
    if (b.name == null) return -1;

    // Cast to lowercase if there is value
    const aName = aName.toLowerCase();
    const bName = bName.toLowerCase();

    if (aName === bName) return 0;
    if (aName < bName) return -1; // Is this asc or desc sorting?? let's check documentation
    return 1;
  });

  const deepFreeze = require('js-flock').deepFreeze;

  const person = {
    fullName: 'test person',
    dob: new Date(),
    address: {
      country: 'testiland',
      city: 'this one'
    }
  }

  Object.freeze(person);

  Object.isFrozen(person); // true
  Object.isFrozen(person.address); // false UH OH

  deepFreeze(person);

  Object.isFrozen(person); // true
  Object.isFrozen(person.address); // true WE HE