Simple MineSweeper Game

minesweeper.js

class Cell {
  constructor (x, y) {
    this.x = x;
    this.y = y;
    this.isMine = false;
    this.isFlagged = false;
    this.isRevealed = false;
    this.neighborMines = 0;
  }
}

class MineSweeper {
  constructor (rows, cols, mines) {
    this.rows = rows;
    this.cols = cols;
    this.mines = mines;
    this.board = this.createBoard();
    this.gameOver = false;
    this.startTime = null;
    this.endTime = null;
    
    this.placeMines();
    this.setNeighborsMineCount();
  }
  
  createBoard () {
    let board = [];
    for (let i = 0; i < this.rows; i ++) {
      board.push([]);
      for (let j = 0; j < this.cols; j ++) {
        board[i].push(new Cell(i, j));
      }
    }
    return board;
  }
  
  placeMines () {
    if (this.mines > this.rows * this.cols) {
      this.mines = this.rows * this.cols;
    }
    
    let minesPlaced = 0;
    while (minesPlaced < this.mines) {
      let randomRow = Math.floor(Math.random() * this.rows);
      let randomCol = Math.floor(Math.random() * this.cols);
      if (!this.board[randomRow][randomCol].isMine) {
        this.board[randomRow][randomCol].isMine = true;
        minesPlaced ++;
      }
    }
  }
  
  setNeighborsMineCount () {
    for (let i = 0; i < this.rows; i ++) {
      for (let j = 0; j < this.cols; j ++) {
        let cell = this.board[i][j];
        if (cell.isMine) {
          continue;
        }
        let neighbors = this.getNeighbors(cell);
        let neighborMines = 0;
        for (let neighbor of neighbors) {
          if (neighbor.isMine) {
            neighborMines ++;
          }
        }
        cell.neighborMines = neighborMines;
      }
    }
  }
  
  getNeighbors (cell) {
    let neighbors = [];
    let row = cell.x;
    let col = cell.y;
    for (let i = row - 1; i <= row + 1; i ++) {
      for (let j = col - 1; j <= col + 1; j ++) {
        if (i < 0 || i >= this.rows || j < 0 || j >= this.cols) {
          continue;
        }
        if (i === row && j === col) {
          continue;
        }
        neighbors.push(this.board[i][j]);
      }
    }
    return neighbors;
  }
  
  printBoard () {
    for (let i = 0; i < this.rows; i ++) {
      let row = '';
      for (let j = 0; j < this.cols; j ++) {
        let cell = this.board[i][j];
        if (cell.isRevealed) {
          if (cell.isMine) {
            row += '* ';
          } else {
            row += cell.neighborMines + ' ';
          }
        } else if (cell.isFlagged && !this.gameOver) {
          row += 'F ';
        } else if (this.gameOver) {
          if (cell.isMine && cell.isFlagged) {
            row += 'X ';
          } else if (cell.isMine) {
            row += '* ';
          } else {
            row += '- ';
          }
        } else {
          row += '? ';
        }
      }
      console.log(row);
    }
  }
  
  revealCell (cell) {
    if (this.gameOver) {
      return;
    }
    
    if (cell.isMine) {
      this.endTime = new Date().getTime();
      this.gameOver = true;
      cell.isRevealed = true;
      console.log('Game over!');
      console.log('Play time: %s', this.getPlayTime());
      return;
    }
    
    if (cell.neighborMines === 0) {
      let neighbors = this.getNeighbors(cell);
      for (let neighbor of neighbors) {
        if (!neighbor.isRevealed) {
          neighbor.isRevealed = true;
          this.revealCell(neighbor);
        }
      }
    }
    
    cell.isRevealed = true;
    
    if (this.isGameWon()) {
      this.endTime = new Date().getTime();
      this.gameOver = true;
      this.printBoard();
      console.log('You won!');
      console.log('Play time: %s', this.getPlayTime());
    }
  }
  
  isGameWon () {
    for (let i = 0; i < this.rows; i ++) {
      for (let j = 0; j < this.cols; j ++) {
        if (!this.board[i][j].isRevealed && !this.board[i][j].isMine) {
          return false;
        }
      }
    }
    
    return true;
  }
  
  flagCell (cell) {
    if (this.gameOver) {
      return;
    }
    
    if (cell.isRevealed) {
      return;
    }
    
    cell.isFlagged = !cell.isFlagged;
  }
  
  startGame () {
    this.startTime = new Date().getTime();
    this.gameOver = false;
    const prompt = require('prompt-sync')();
    
    console.log('Welcome to Minesweeper!');
    console.log('(Type \'q\' to quit.)');
    
    this.printBoard();
    
    while (!this.gameOver) {
      let [row, col] = prompt(`Enter row and col (Split by spaces): `)
        .split(' ');
      let isFlag = prompt('Is this a flag? (y/n):') === 'y';
      
      if (row === 'q' || col === 'q') {
        break;
      }
      
      if (col <= 0 || col > this.cols || row <= 0 || row > this.rows) {
        console.log('Invalid row or col!');
        break;
      }
      
      if (!row || !col) {
        continue;
      }
      
      let cell = this.board[row - 1][col - 1];
      
      if (cell.isRevealed) {
        console.log('Cell already revealed!');
        continue;
      }
      
      if (isFlag) {
        this.flagCell(cell);
      } else {
        if (cell.isFlagged) {
          this.flagCell(cell);
        } else {
          this.revealCell(cell);
        }
      }
      this.printBoard();
    }
  }
  
  getPlayTime () {
    const moment = require('moment');
    return moment.duration(this.endTime - this.startTime, 'milliseconds')
      .humanize();
  }
}

new MineSweeper(5, 5, 5).startGame();