async iterators (its not finished yet)

const createStore = () => {
  const tables = {
    customer: {
      1: {name: 'John'},
      2: {name: 'Mattias'},
      3: {name: 'Kim'},
    },
    food: {
      1: ['cake', 'waffle'],
      2: ['coffee'],
      3: ['apple', 'carrot'],
    },
  };
  
  return{
    get: (table, id) => tables[table][id]
  };
}

const store = createStore();

const customers = {
  [Symbol.iterator]: () => {
    let i = 0;
    return {
      next: () => {
        i++;
        const customer = store.get('customer', i)
        
        if(!customer) return {done: true}
        
        customer.foods = store.get('food', i);
        return {
          value: customer,
          done: false
        }
      }
    }
  }
}

for (const why of customers){
  console.log('why ->', why);
}

Destructuring of Arrays using iterators

const array = ['a', 'b', 'c', 'd', 'e'];
const [first, ,third, ,last] = array;

// is similar to this below..

const array = ['a', 'b', 'c', 'd', 'e'];

const iterator = array[Symbol.iterator]();

const first = iterator.next().value
iterator.next().value // Since it was skipped, so it's not assigned
const third = iterator.next().value
iterator.next().value // Since it was skipped, so it's not assigned
const last = iterator.next().value

console.log('%c first: %s, third: %s, last: %s','color: red; font-weight: bold;', first, third, last);

Iterators in JavaScript

function randomItem(arr){
  const randomIndex = {
    max: arr.length - 1,
  };
  const ran = Math.floor(Math.random() * randomIndex.max) + 1;
  return arr[ran];
}

// console.log(randomItem(['a', 'b', 'c', 'd', 'e']));

const makeDragon = () => {
  const dragonSize = ['big', 'medium', 'tiny', 'mega'];
  const dragonAbility = ['fire', 'ice', 'lighting'];
  
  return randomItem(dragonSize) + " " + randomItem(dragonAbility) + " " + 'dragon';
}

// console.log("%c %s", 'color: white; font-weight: bold;', makeDragon());

// using iterator
const dragonArmy = {
  [Symbol.iterator]: () => {
    return{
      next: () => {
        const enoughDragonsSpawned = Math.random() > 0.75;
        if(!enoughDragonsSpawned)
          return{
            value: makeDragon(),
            done: false,
          }
        return { done: true }
      }
    }
  }
}

// using generator[syntactic sugar of `iterator`]
const dragonArmy = {
  [Symbol.iterator]: function* (){
    while(true){
      const enoughDragonsSpawned = Math.random() > 0.75;
      if(enoughDragonsSpawned) return;
      yield makeDragon();
    }
  }
}

// for(const dragon of dragonArmy){
//   console.log("%c %s", 'color: red; font-weight: bold;', dragon);
// }