js-array-destructuring.js

// ************************************************
// ****************** Arrays *********************
// ************************************************

const campuses = ['madrid', 'barcelona', 'miami'];
const [firstCampus, secondCampus, thirdCampus] = campuses;

console.log(thirdCampus); // miami

// Put the first item in the array in a variable:

const [first] = campuses;
console.log(first); // <== madrid

// Skip the first element, and take the second one only:
const [, second] = campuses;
console.log(second); // <== barcelona

// Skip the first and the second element, and take the third one only:

const [, , campus3] = campuses;
console.log(campus3); // <== miami

// Default values

const [campus1, campus2, campus3, campus4] = campuses;
console.log(campus4); // ==> undefined

// But we can assign the value to the additional variable (campus4):

const [campus1, campus2, campus3, campus4 = 'paris'] = campuses;
console.log(campus4); // ==> paris

// Nested arrays and destructuring

const europeanCampuses = [
  ['madrid', 'es'],
  ['barcelona', 'es'],
  ['berlin', 'de'],
  ['paris', 'fr'],
  ['amsterdam', 'nl'],
  ['lisbon', 'pt']
];

const [
  [campusSpain1],
  [campusSpain2, country],
  [campus5, theCountry]
] = europeanCampuses;

console.log(campusSpain1, campusSpain2, country, theCountry);
// ==> 'madrid' 'barcelona' 'es' 'de'