hof-5-is-same-language.js

// ***********************************************************************************************************************
// https://www.codewars.com/kata/coding-meetup-number-6-higher-order-functions-series-can-they-code-in-the-same-language

// You will be given an array of objects (associative arrays in PHP) representing data about developers who have signed up to attend the next coding meetup that you are organising.

// Your task is to return either:
// true if all developers in the list code in the same language; or
// false otherwise.
// For example, given the following input array:
// var list1 = [
//   { firstName: 'Daniel', lastName: 'J.', country: 'Aruba', continent: 'Americas', age: 42, language: 'JavaScript' },
//   { firstName: 'Kseniya', lastName: 'T.', country: 'Belarus', continent: 'Europe', age: 22, language: 'JavaScript' },
//   { firstName: 'Hanna', lastName: 'L.', country: 'Hungary', continent: 'Europe', age: 65, language: 'JavaScript' },
// ];

// your function should return true.
// ***********************************************************************************************************************

// solution 1:

function isSameLanguage(list) {
  for (let i = 0; i < list.length; i++) {
    if (list[0].language !== list[i].language) return false;
  }
  return true;
}

// solution 2:
const isSameLanguage = list => list.every(({ language }) => language === list[0].language);