POS Sample Project

index.js

// Define very hea database
const foodDatabase = {
  "🍔": { id: "🍔", type: "main", price: 25 },
  "🥪": { id: "🥪", type: "main", price: 20 },
  "🌭": { id: "🌭", type: "main", price: 30 },
  "🥗": { id: "🥗", type: "side", price: 20 },
  "🍟": { id: "🍟", type: "side", price: 15 },
  "🥛": { id: "🥛", type: "drink", price: 12 },
  "🥤": { id: "🥤", type: "drink", price: 10 },
  "🧋": { id: "🧋", type: "drink", price: 20 }
}
console.log('Defined food database:\n', foodDatabase)

function compareFoodByPrice(foodA, foodB) {
  return foodB.price - foodA.price
}

function processFoodItems(input) {
  // Query food items from input ID
  const foodItems = []
  for (let i = 0; i < input.length; i++) {
    const foodID = input[i]
    const food = foodDatabase[foodID]
    foodItems.push(food)
  }

  const mainItems  = []
  const sideItems  = []
  const drinkItems = []
  
  for (let i = 0; i < foodItems.length; i++) {
    const food = foodItems[i];
    switch (food.type) {
      case 'main':
        mainItems.push(food)
        break
      case 'side':
        sideItems.push(food)
        break
      case 'drink':
        drinkItems.push(food)
        break
    }
  }

  mainItems.sort(compareFoodByPrice)
  sideItems.sort(compareFoodByPrice)
  drinkItems.sort(compareFoodByPrice)

  console.log('\n\nStep 1: Sort grouped items by price in DESC order:')

  console.log('\nMain Items:')
  console.log(mainItems)

  console.log('\nSide Items:')
  console.log(sideItems)

  console.log('\nDrink Items:')
  console.log(drinkItems)

  const maxNumberOfSets = Math.min(mainItems.length, sideItems.length, drinkItems.length)
  console.log('\nAlso, we found the possible maximum number of sets (pick the minimum length of arrays from above):')
  console.log(maxNumberOfSets) // 1


  const sets = []
  const canFormSets = maxNumberOfSets > 0
  if (canFormSets) {
    for (let i = 0; i < maxNumberOfSets; i++) {
      if (mainItems[0] && sideItems[0] && drinkItems[0]) {
        // Remove the first item of the corresponding type of food items if exist
        const main  = mainItems.shift()
        const side  = sideItems.shift()
        const drink = drinkItems.shift()
        console.log('\nFound a set: ', main.id, side.id, drink.id)
        // Form and add set to the result if there are main, side and drink
        sets.push([main, side, drink])
      }
    }
  }
  console.log('\n\nStep 3: Combined food items into sets:\n', sets)

  // Put the rest of the food items which can't form a set to the result
  const remainingItems = mainItems.concat(sideItems).concat(drinkItems)
  console.log('\n\nStep 4: Remaining food items:\n', remainingItems)

  return sets.concat(remainingItems)
}

const result1 = processFoodItems(["🍟", "🥛", "🍔", "🍟"])
console.log('\n\nResult 1:')
console.log(result1)
/**
 * [
 *   [
 *     { 'id': '🍔', 'type': 'main', 'price': 25 },
 *     { 'id': '🍟', 'type': 'side', 'price': 15 },
 *     { 'id': '🥛', 'type': 'drink' 'price': 12 },
 *   ],
 *   { 'id': '🍟', 'type': 'side', 'price': 15 },
 * ]
 */

const result2 = processFoodItems(["🍟", "🥛"])
console.log('\n\nResult 2:')
console.log(result2)
/**
 * [
 *   { id: '🍟', type: 'side', price: 15 },
 *   { id: '🥛', type: 'drink', price: 12 }
 * ]
 */


const result3 = processFoodItems(["🥗", "🥛", "🍔", "🍟", "🌭"])
console.log('\n\nResult 3:')
console.log(result3)
/**
 * [
 *   [
 *     { id: '🌭', type: 'main', price: 30 },
 *     { id: '🥗', type: 'side', price: 20 },
 *     { id: '🥛', type: 'drink', price: 12 }
 *   ],
 *   { id: '🍔', type: 'main', price: 25 },
 *   { id: '🍟', type: 'side', price: 15 }
 * ]
 */