Javascript Bowling Kata

javascript.js

function bowlingScore(frames) {
  const rolls = frames.split("").filter(function(value, index) { return value != " " });
  var frames = getFramesFromRolls(rolls);
  var score = calculateScoreFromFrames(rolls, frames);
  return score;
}

function getFramesFromRolls(rolls) {
  
  if (rolls === undefined || rolls.length == 0) { return []; }
  
  var frames= [];
  var frame = new Frame(0);
  
  for(var i = 0; i < rolls.length; i++)
  {
    if(frames.length < 9) {
      frame.addRoll(i);
      if(frame.getRolls().length == 2 || hasSpare(rolls, frame.getRolls()) || hasStrike(rolls, frame.getRolls())) {
        frames.push(frame);
        frame = new Frame(frames.length);
      }
    } else {
      // final frame
      frame.addRoll(i);
    }
  }
  frames.push(frame);
  return frames;
}

function calculateScoreFromFrames(rolls, frames) {
  if (frames === undefined || frames.length == 0) { return []; }

  for(var i = 0; i < frames.length; i++)
  {
    var frame = frames[i];
    if(i < 9) {
      var rollValuesInThisFrame = getRollValues(rolls, frame.getRolls());
      var score = getScoresFromRollValues(rollValuesInThisFrame);
      var firstRollPosition = frame.getRolls()[0];
      var futures = [];
      var spare = hasSpare(rolls, frame.getRolls());
      var strike = hasStrike(rolls, frame.getRolls());
      var bonus = 0;
      if(strike) { 
        if(rolls[firstRollPosition + 1] !== undefined) futures.push(firstRollPosition + 1);
        if(rolls[firstRollPosition + 2] !== undefined) futures.push(firstRollPosition + 2);
      }
      else if(spare) {
        if(rolls[firstRollPosition + 2] !== undefined) futures.push(firstRollPosition + 2);
      }
      if(futures.length > 0) {
        bonus = getScoresFromRollValues(getRollValues(rolls, futures));
      }
      frame.setBonus(bonus);
      frame.setScore(score);
      
    } else {
      
      var rollValuesInThisFrame = getRollValues(rolls, frame.getRolls());
      var score = getScoresFromRollValues(rollValuesInThisFrame);
      
      frame.setBonus(0);
      frame.setScore(score);
    }
  }

  var result = frames
      .map(function(r) { return r.getTotal(); })
      .reduce(function(a,b) { return a + b; });
  
  return result;
}

function hasSpare(rolls, positions) {
  return getRollValues(rolls, positions).includes("/");
}

function hasStrike(rolls, positions) {
  return getRollValues(rolls, positions).includes("X");
}

function getRollValues(rolls, positions) {
  return positions.map(function(i) { return rolls[i]; });
}

function getScoresFromRollValues(values) {
  return values
    .map(function(element, index) {
      if(element == "X") { return 10; }
      if(element == "/") { return 10 - parseInt(values[index - 1]); } // hack
      if(values[index + 1] == undefined) { return parseInt(element); } 
      return parseInt(element);
    })
    .reduce(function(a,b) { return a + b; }); 
}

class Frame {

  constructor(id)
  {
    this.rolls = [];
    this.bonus = 0;
    this.score = 0;
    this.id = id;
  };
  
  setBonus(value) { this.bonus = value; }
  setScore(value) { this.score = value; }
  getTotal() { return this.score + this.bonus; }
  addRoll(roll) { this.rolls.push(roll); }
  getRolls() { return this.rolls; }
}