Destructuring examples

LunchNLearn-ES6Destructuring.js

// Simple one to one assignment
var [a, b, c] = [1, 2, 3];
console.log(`a is ${a}`);
console.log(`b is ${b}`);
console.log(`c is ${c}`);

// Assigning the remaining elements
var [alpha, beta, gamma, ...theRest] = [1,2,3,4,5,6,7,8,9,10];
console.log(`alpha is ${alpha}`);
console.log(`beta is ${beta}`);
console.log(`gamma is ${gamma}`);
console.log(`theRest is ${theRest}`);

// Skipping elements
var [one, , three, , five] = [1,2,3,4,5];
console.log(one);
console.log(three);
console.log(five);

// Direct pull of object parameter properties

function fullName({ first: firstName, last: lastName}) {
  return `${firstName} ${lastName}`;
}

var awesomestPerson = { first: 'Juan', last: 'Medina'};

console.log(`The most awesome person in the whole world is ${fullName(awesomestPerson)}`);

// Defaulting object parameters and the full object
function carelessFullName({ first: firstName = 'Marty', last: lastName = 'McFly'} = { first: 'John', last: 'Doe'}) {
//function carelessFullName({ first: firstName = 'Marty', last: lastName = 'McFly'} = { first: firstName = 'John', last: lastName = 'Doe'}) {  
  return `${firstName} ${lastName}`;
}

var juanToTheFuture = {first: 'Juan'};
var martyFromColombia = {last: 'Medina'}
var nobodyCares = {};

console.log(`juanToTheFuture is ${carelessFullName(juanToTheFuture)}`);
console.log(`martyFromColombia is ${carelessFullName(martyFromColombia)}`);
console.log(`nobodyCared is ${carelessFullName(nobodyCares)}`);
console.log(`empty Parameter yields ${carelessFullName()}`);

// Object destructuring
var elGrandeBoardGame = {
  title : 'El Grande',
  authors : [ { name :'Wolfgang Kramer'}],
  categories : ['Area Control', 'Spain', 'Euro'],
  publisher : [ { name: 'Rio Grande Games', country : 'United States' }, { name: 'Libelund' , country: 'France'} ]
}

var { title : title, authors: [{ name : oneAuthor}] , categories: [firstCategory], publisher : [ { name :firstPublisher}] } = elGrandeBoardGame; 
console.log(`${title} by ${oneAuthor} is a(n) ${firstCategory} game published by ${firstPublisher}`);

var test = [];

console.log(test instanceof Array);

var dictionary = [
  { key: 'first', value :'1' },
  { key: 'second', value :'2' },
  { key: 'third', value :'3' },
  { key: 'fourth', value :'4' }
];

console.log(dictionary instanceof Array);

console.log(dictionary);

for (let { key: key } of dictionary) {
  console.log(key);
}

var supers = [
  { firstName: 'Kal', lastName :'El', heroName: 'Superman', powers : ['Superstrength', 'X-Ray vision'] },
  { firstName: 'Bruce', lastName :'Wayne', heroName: 'Batman', powers : ['Gadgets', 'Detective', ''] },  
  { firstName: 'Peter', lastName :'Parker', heroName: 'Spiderman', powers : ['Spider Sense', 'Super Agility'] }
];

for (let { heroName : superHero } of supers) {
  console.log(superHero)
}

for (let test in supers) {
  console.log(test);
}