Untitled

const SUITS = ["clubs", "hearts", "diamonds", "spades"]
const RANKS = [
  "A",
  "2",
  "3",
  "4",
  "5",
  "6",
  "7",
  "8",
  "9",
  "10",
  "J",
  "Q",
  "K",
  "Joker"
]

class Card {
  constructor(suit, rank) {
    this.suit = suit
    this.rank = rank
  }
}

function isValidHand(cards) {
  if (cards.length != 5) return false

  let ranks = new Map()
  let suits = new Map()
  let jokerCount = 0

  for (let i = 0; i < cards.length; i++) {
    if (cards[i].rank == "Joker") {
      jokerCount++
      continue
    }

    if (!ranks.has(cards[i].rank)) {
      ranks.set(cards[i].rank, 1)
    } else {
      let temp = ranks.get(cards[i].rank)
      ranks.set(cards[i].rank, temp + 1)
    }

    if (!suits.has(cards[i].suit)) {
      suits.set(cards[i].suit, 1)
    } else {
      let temp = suits.get(cards[i].suit)
      suits.set(cards[i].suit, temp + 1)
    }
  }

  if (jokerCount == 5) return true 

  let rankFrequencies = [...ranks.values()]
  let rankValues = [...ranks.keys()]

  // Flush - makes straight flush redundant 
  if (suits.size == 1) return true

  // 4 of a kind - makes 5 of a kind redundant 
  for (let i = 0; i < rankFrequencies.length; i++) {
    if (rankFrequencies[i] + jokerCount >= 4) return true
  }

  // Full House
  if (jokerCount == 0) {
    if (ranks.size == 2 && (rankFrequencies[0] == 2 || rankFrequencies[0] == 3)) return true 
  } else if (jokerCount == 1) {
    if (ranks.size == 2) return true
  } else if (jokerCount == 2 || jokerCount == 3) {
    if (ranks.size == 1 || ranks.size == 2) return true 
  } else if (jokerCount > 3) return true 

  // Straight
  if (rankValues.length + jokerCount != 5) return false 

  let weightArr = []
  for (let i = 0; i < rankValues.length; i++) {
    weightArr.push(RANKS.indexOf(rankValues[i]))
  }
  weightArr.sort((a, b) => a - b)

  if (weightArr[weightArr.length - 1] - weightArr[0] < 5) return true

  return false
}