scoringEngine.js

let count = 1;

export const singles = (value, dice) => {
  return dice.filter( d => d === value ).reduce( (total, val) => {
    return total + value;
  }, 0);
}

export const addAllDice = (type, dice) => {
  let totals = [];
  const empty = [0, 0, 0, 0, 0];

  switch(type) {
    case 'Three Of A Kind':
      totals = validateThreeOfAKind(dice) ? dice : empty
      break;
    case 'Four Of A Kind':
      totals = validateFourOfAKind(dice) ? dice : empty
      break;
    default:
      totals = dice;
  }

  return totals.reduce( (total, val) => {
    return total + val;
  }, 0);
}

export const staticScore = (type, dice) => {
  switch(type) {
    case 'Full House':
      return validateFullHouse(dice) ? 25 : 0
    case 'Low Straight':
      return validateLowStraight(dice) ? 30 : 0
    case 'High Straight':
      return validateHighStraight(dice) ? 40 : 0
    case 'Yahtzee':
      return validateYahtzee(dice) ? 50 : 0
  }
}

const validateFullHouse = (dice) => {
  let hasTwo = false;
  let hasThree = false;
  let split = splitArray(dice);
  for ( let arr of split.newArray ) {
    if (arr.length === 3 )
      hasThree = true;
    if (arr.length === 2 )
      hasTwo = true;
  }

  return hasTwo && hasThree
}

const validateLowStraight = (dice) => {
  let count = findSeq(dice.sort());
  return count >= 4;
}

const validateHighStraight = (dice) => {
  let count = findSeq(dice.sort());
  return count === 5;
}

const validateYahtzee = (dice) => {
  let matches = 0;
  let val = dice[0];
  matches = dice.filter( i => i === val ).length
  return matches === 5;
}

const validateThreeOfAKind = (dice) => {
  let hasScore = false;
  let split = splitArray(dice);
  for ( let arr of split.newArray ) {
    if (arr.length >= 3 )
      hasScore = true;
  }

  return hasScore;
}

const validateFourOfAKind = (dice) => {
  let hasScore = false;
  let split = splitArray(dice);
  for ( let arr of split.newArray ) {
    if (arr.length >= 4 )
      hasScore = true;
  }

  return hasScore;
}

const splitArray = (dice) => {
  let split = dice.sort().reduce( (acc, val) => {
    let inner;
    if (acc.previous !== val) {
      inner = [];
    } else {
      inner = acc.newArray.pop();
    }

    inner.push(val);
    acc.previous = val;
    acc.newArray.push(inner);
    return acc;
    }, {
      previous: null,
      newArray: []
  });

  return split;
}

const findSeq = (dice) => {
  let count = 1;
  for( let i = 0; i < dice.length; i++) {
    if (dice[i + 1] - 1 === dice[i])
      ++count
  }
  return count
}