destructuringArrays.js

'use strict';

// Data needed for a later exercise
const flights =
  '_Delayed_Departure;fao93766109;txl2133758440;11:25+_Arrival;bru0943384722;fao93766109;11:45+_Delayed_Arrival;hel7439299980;fao93766109;12:05+_Departure;fao93766109;lis2323639855;12:30';

// Data needed for first part of the section
const restaurant = {
  name: "Vini's Curry House",
  location: '123 Gora Way, Mumbai, India',
  categories: ['Punjabi', 'Bengali', 'Madras', 'Neplai'],
  starterMenu: ['Samosa', 'Pakora', 'Nan', 'Kebab'],
  mainMenu: ['Dosa', 'Chicken Madras', 'Tandoori Halibut'],

  //   openingHours: {
  //     thu: {
  //       open: 12,
  //       close: 22,
  //     },
  //     fri: {
  //       open: 11,
  //       close: 23,
  //     },
  //     sat: {
  //       open: 0, // Open 24 hours
  //       close: 24,
  //     },
  //   },

  order: function (starterIndex, mainIndex) {
    return [this.starterMenu[starterIndex], this.mainMenu[mainIndex]];
  },
};

// Destructuring Arrays
// Destructuring is an ES6 feature of unpacking values
// from and array or object to a variable
// not destructive

const arr = [2, 3, 4];

// old way

// const a = arr[0];
// const b = arr[1];
// const c = arr[2];

// new way (destructuring)
// destructuring works from the Right side of assignment

const [a, b, c] = arr;
console.log(a, b, c);

// take first and second categories
let [first, second] = restaurant.categories;
console.log(first, second);

// take first and third (skip second)
const [firstAgain, , third] = restaurant.categories;
console.log(firstAgain, third);

// take second and fourth (skip second)
const [, secondAgain, , fourth] = restaurant.categories;
console.log(secondAgain, fourth);

// switch main and secondary category (Bengali first, then Punjabi)

[first, second] = [second, first];
console.log(first, second); // Not permanent

// All elements with spread... oper
console.log(...restaurant.categories);

// functions multiple values

console.log(restaurant.order(2, 2));

// simply destruct: console.log(restaurant.order(2,2));

// Recieve 2 return values from  a function
const [starter, main] = restaurant.order(2, 0);
console.log(starter, main);

// Nested arrays

const nestedArr = [2, 4, [5, 6]];
// const [i, , j] = nestedArr;
// console.log(i, j);

const [i, , [j, k]] = nestedArr;
console.log(i, j, k);

// Default values
// useful when working with APIs

const [p=1, q=1, r=1] = [8, 9];
console.log(p, q, r);