Bowling challenge

frame.js

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+class Frame {
+  constructor() {
+    this.rolls = [];
+    this.regularPoints = 0;
+    this.bonusPoints = 0;
+  };
+
+  roll(points) {
+    // check if frame has already ended
+    if (this.rolls.length == 2 || this.rolls.includes(10)) {
+      throw new Error('Tried to add points to a frame that is already over');
+      // check for invalid scores being inputted
+    } else if(points < 0 || points > 10 ) {
+      throw new Error(`Tried to add an invalid roll score (${points})`);
+    } else if ((this.regularPoints + points) > 10) {
+      throw new Error(`Tried to add roll that would exceed max score in a frame (${this.regularPoints} + ${points})`);
+    } else {
+      this.rolls.push(points);
+      this.regularPoints += points;
+    };
+  };
+  // is this function necessary? This logic could be in Game
+  playFrame(points_array) {
+    points_array.forEach((points) => {
+      this.roll(points);
+    });
+  }
+
+  isStrike() {
+    return (this.rolls.includes(10) && this.rolls.length == 1 ? true : false);
+  }
+
+  isSpare() {
+    return (this.regularPoints == 10 && this.rolls.length == 2 ? true : false);
+  }
+}
+module.exports = Frame;

frame.test.js

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+const Frame = require('./frame');
+
+describe('Frame class unit test', () => {
+  describe('constructor', () => { 
+    it('initliases with empty array this.rolls', () => {
+      frame = new Frame();
+      expect(frame.rolls).toEqual([]);
+    })
+
+    it('initliases with bonus points & regular points values of 0', () => {
+      frame = new Frame();
+      expect(frame.bonusPoints).toEqual(0);
+      expect(frame.regularPoints).toEqual(0);
+
+    })
+  });
+
+  describe('.roll', () => { 
+    it('adds roll score to this.rolls', () => {
+      frame = new Frame();
+      frame.roll(5);
+      expect(frame.rolls[0]).toEqual(5);
+      expect(frame.rolls.length).toEqual(1);
+      frame.roll(5);
+      expect(frame.regularPoints).toEqual(10);
+      expect(frame.bonusPoints).toEqual(0);
+    });
+
+    it('refuses to add a roll if two have already been scored', () => {
+      expect(() => {
+        frame = new Frame();
+        frame.roll(5);
+        frame.roll(3);
+        frame.roll(6)
+      }).toThrow('Tried to add points to a frame that is already over');
+    });
+
+    it('refuses to add a roll if a strike was made on first roll=', () => {
+      frame = new Frame();
+      frame.roll(10);
+      expect(() => frame.roll(6)).toThrow('Tried to add points to a frame that is already over');
+      expect(frame.rolls).toEqual([10]);
+    });
+
+    it('returns error message given an invalid roll score', () => {
+      frame = new Frame();
+      expect(() => frame.roll(13)).toThrow('Tried to add an invalid roll score (13)');
+      expect(() => frame.roll(-5)).toThrow('Tried to add an invalid roll score (-5)');  
+    });
+
+    it('returns error message if roll would exceed max score in a frame', () => {
+      frame = new Frame();
+      frame.roll(5);
+      expect(() => frame.roll(7)).toThrow('Tried to add roll that would exceed max score in a frame (5 + 7');   
+    }); 
+  });
+
+  it('takes an array of points for .playFrame() and rolls for each one', () => {
+    frame = new Frame();
+    frame.playFrame([5, 3]);
+    expect(frame.regularPoints).toEqual(8)
+  });
+
+  describe('.isSpare()', () => {
+    it('returns true when frame is a spare', () => {
+      frame = new Frame();
+      frame.playFrame([5, 5]);
+      expect(frame.isSpare()).toEqual(true);
+    });
+
+    it('returns true when frame is a spare with a 10 on 2nd roll', () => {
+      frame = new Frame();
+      frame.playFrame([0, 10]);
+      expect(frame.isSpare()).toEqual(true);
+    });
+
+    it('returns false when frame is a strike', () => {
+      frame = new Frame();
+      frame.playFrame([10]);
+      expect(frame.isSpare()).toEqual(false);
+    });
+  });
+
+  describe('.isStrike()', () => {
+    it('returns true when frame is a strike', () => {
+      frame = new Frame();
+      frame.playFrame([10]);
+      expect(frame.isStrike()).toEqual(true);
+    });
+
+    it('returns false when frame is a spare', () => {
+      frame = new Frame();
+      frame.playFrame([2, 8]);
+      expect(frame.isStrike()).toEqual(false);
+    });
+  });
+});

game.js

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+class Game {
+  constructor(frameClass) {
+    this.grandTotal = 0;
+    this.frames = [];
+    for(let i = 0; i < 10; i++) {
+      let frame = new frameClass();
+      this.frames.push(frame);
+    };
+  };
+
+  play(scoresArray) { // take a 2D array, 1 array for each frame. If strike, array length will be 1
+    this.frames[0].playFrame(scoresArray[0]);
+    // no bonus points to allocate after first frame
+    for (let i = 1; i < 10; i++) {
+      this.frames[i].playFrame(scoresArray[i]);
+      this.allocateBonusPoints(i);
+    }
+    if (this.frames[9].isStrike() || this.frames[9].isSpare()) {
+      // Bonus rolls after the final frame provided from UI as addl array element
+      this.playFinalFrameBonusRolls(scoresArray[10]);
+    }
+    this.calculateGrandTotal();
+  };
+
+  allocateBonusPoints(index) {
+    if (this.frames[index-1].isSpare()) {
+      this.frames[index-1].bonusPoints += this.frames[index].rolls[0]; 
+    } else if (this.frames[index-1].isStrike()) {
+      this.frames[index-1].bonusPoints += this.frames[index].regularPoints;
+      // if this is at least the 3rd frame & have been 2 consecutive strikes before this frame
+      if (index >= 2 && this.frames[index-2].isStrike()) {
+        this.frames[index-2].bonusPoints += this.frames[index].rolls[0]
+      };
+    };
+  };
+
+  playFinalFrameBonusRolls(bonusRollsArray) {
+    bonusRollsArray.forEach((points) => {
+      this.frames[9].bonusPoints += points;
+    });
+    // If player had a strike in frame 9 and 10, allocate the first bonus roll as bonus point to frame 9:
+    if (this.frames[9].isStrike() && this.frames[8].isStrike()) {
+      this.frames[8].bonusPoints += bonusRollsArray[0];
+    };
+  };
+
+  calculateGrandTotal() {
+    this.frames.forEach((frame) => {
+      this.grandTotal += (frame.regularPoints + frame.bonusPoints);
+    });
+  };
+
+  isGutterGame() {
+    return (this.grandTotal == 0 ? true : false);
+  };
+
+  isPerfectGame() {
+    return (this.grandTotal == 300 ? true : false);
+  };
+};
+
+module.exports = Game;

game.test.js

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+const Game = require('./game');
+const Frame = require('./frame');
+
+jest.mock('./frame.js');
+
+describe('Game class unit test', () => {
+  beforeEach(() => {
+    Frame.mockClear();
+
+    mockFrame = {
+      playFrame: jest.fn(),
+      isSpare: jest.fn(),
+      isStrike: jest.fn(),
+      rolls: jest.fn(),
+      regularPoints: jest.fn(),
+      bonusPoints: 0,
+    };
+
+    Frame.mockImplementation(() => mockFrame); // mock the constructor of Frame to return our mockFrame
+  });
+
+  describe('constructor', () => {
+    it('initializes with an array of 10 frames', () => {
+      let game = new Game(Frame);
+      expect(Frame).toHaveBeenCalledTimes(10);
+      expect(game.frames.length).toEqual(10);
+    });
+
+    it('initializes with a grand total score of 0', () => {
+      let game = new Game(Frame);
+      expect(game.grandTotal).toEqual(0);
+    });
+  });
+
+  describe('.play()', () => {
+    it('calls .playFrame on each of the 10 frames without spare or strike in last frame', () => {
+      let game = new Game(Frame);
+      const scores = [[1, 4], [4, 5], [6, 4], [5, 5], [10], [0, 1], [7, 3], [6, 4], [10], [2, 7]];
+      game.frames[3].rolls.mockImplementation(() => [5, 5]);
+      game.frames[4].rolls.mockImplementation(() => [10]);
+      game.frames[7].rolls.mockImplementation(() => [6, 4]);
+      game.frames[8].rolls.mockImplementation(() => [10]);
+      game.frames[9].rolls.mockImplementation(() => [2, 7]);
+      game.play(scores);
+      expect(mockFrame.playFrame).toHaveBeenCalledTimes(10);
+      expect(mockFrame.playFrame).toHaveBeenCalledWith(scores[0]);
+      expect(mockFrame.playFrame).toHaveBeenCalledWith(scores[1]);
+      expect(mockFrame.playFrame).toHaveBeenCalledWith(scores[9]);
+    });
+
+    it('Score a complex game correctly', () => {
+      let game = new Game(Frame);
+      const scores = [[1, 4], [4, 5], [6, 4], [5, 5], [10], [0, 1], [7, 3], [6, 4], [10], [2, 8], [6]];
+      game.frames[0].rolls.mockImplementation(() => [1, 4]);
+      game.frames[0].isSpare.mockImplementation(() => false);
+      game.frames[0].isStrike.mockImplementation(() => false);
+      game.frames[0].regularPoints.mockImplementation(() => 5);
+
+      game.frames[1].rolls.mockImplementation(() => [4, 5]);
+      game.frames[1].isSpare.mockImplementation(() => false);
+      game.frames[1].isStrike.mockImplementation(() => false);
+      game.frames[1].regularPoints.mockImplementation(() => 9);
+
+      game.frames[2].rolls.mockImplementation(() => [6, 4]);
+      game.frames[2].isSpare.mockImplementation(() => true);
+      game.frames[2].isStrike.mockImplementation(() => false);
+      game.frames[2].regularPoints.mockImplementation(() => 10);
+
+
+      game.frames[3].rolls.mockImplementation(() => [5, 5]);
+      game.frames[3].isSpare.mockImplementation(() => true);
+      game.frames[3].isStrike.mockImplementation(() => false);
+      game.frames[3].regularPoints.mockImplementation(() => 10);
+
+
+      game.frames[4].rolls.mockImplementation(() => [10]);
+      game.frames[4].isStrike.mockImplementation(() => true);
+      game.frames[4].isSpare.mockImplementation(() => false);
+      game.frames[4].regularPoints.mockImplementation(() => 10);
+
+
+      game.frames[5].rolls.mockImplementation(() => [0, 1]);
+      game.frames[5].isSpare.mockImplementation(() => false);
+      game.frames[5].isStrike.mockImplementation(() => false);
+      game.frames[5].regularPoints.mockImplementation(() => 10);
+
+      game.frames[6].rolls.mockImplementation(() => [7, 3]);
+      game.frames[6].isSpare.mockImplementation(() => true);
+      game.frames[6].isStrike.mockImplementation(() => false);
+      game.frames[6].regularPoints.mockImplementation(() => 10);
+
+
+      game.frames[7].rolls.mockImplementation(() => [6, 4]);
+      game.frames[7].isSpare.mockImplementation(() => true);
+      game.frames[7].isStrike.mockImplementation(() => false);
+      game.frames[7].regularPoints.mockImplementation(() => 10);
+
+
+      game.frames[8].rolls.mockImplementation(() => [10]);
+      game.frames[8].isStrike.mockImplementation(() => true);
+      game.frames[8].isSpare.mockImplementation(() => false);
+      game.frames[8].regularPoints.mockImplementation(() => 10);
+
+
+      game.frames[9].rolls.mockImplementation(() => [2, 8]);
+      game.frames[9].isSpare.mockImplementation(() => true);
+      game.frames[9].isStrike.mockImplementation(() => false);
+      game.frames[9].regularPoints.mockImplementation(() => 10);
+
+      game.play(scores);
+
+      expect(game.grandTotal).toEqual(133);
+    });
+  });
+});
+