[JavaScript] - Map

SOURCE

//#region Maps - Fundamental

const map = new Map();
map.set('name', 'Classico Italiano');
map.set(1, 'Firenze, Italy');
map.set(2, 'Lisbon, Portugal');
map
  .set('categories', ['Italian', 'Pizzeria', 'Vegetarian', 'Organic'])
  .set('open', 11)
  .set('close', 23)
  .set(true, 'We are open :D')
  .set(false, 'We are closed :(');
map.set(document.querySelector('h1'), 'Heading');

console.log(map.get('name'));
console.log(map.get(true));
console.log(map.get(1));

const time = 21;
console.log(map.get(time > map.get('open') && time < map.get('close')));

console.log(map.has('categories'));
map.delete(2);
map.set([1, 2], 'Test');

console.log(map);

// this one won't work since [1, 2] here is not the same object as the one above. Those are two different objects in the heap.
console.log(map.get([1, 2])); // undefined

// this will work as they both point to the same address
const array = [1, 2];
map.set(array, 'Test');
console.log(map.get(array));

const restaurant = {
  name: 'Classico Italiano',
  location: 'Via Angelo Tavanti 23, Firenze, Italy',
  categories: ['Italian', 'Pizzeria', 'Vegetarian', 'Organic'],
  starterMenu: ['Focaccia', 'Bruschetta', 'Garlic Bread', 'Caprese Salad'],
  mainMenu: ['Pizza', 'Pasta', 'Risotto'],

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

//#region Maps - Iteration
const question = new Map([
  ['question', 'What programming language is the best?'],
  [1, 'C'],
  [2, 'Java'],
  [3, 'JavaScript'],
  ['correct', 3],
  [true, 'Correct 🎉'],
  [false, 'Try Again'],
]);
console.log(question);

// convert object to map
console.log(Object.entries(restaurant.openingHours));
const hoursMap = new Map(Object.entries(restaurant.openingHours));
console.log(hoursMap);

// Quiz app
console.log(question.get('question'));
for (const [key, value] of question) {
  if (typeof key === 'number') console.log(`Answer ${key}: ${value}`);
}

// const answer = Number(prompt('Your answer'));
const answer = 3;
console.log(answer);
console.log(question.get(answer === question.get('correct')));

// convert map to array
console.log([...question]);
// console.log(question.entries());
console.log([...question.keys()]);
console.log([...question.values()]);

//#endregion

vxhviet/map.md

[JavaScript] - Map