minesweeper http://codingdojo.org/kata/Minesweeper/

minesweeper.js

class Minesweeper {
  constructor(cols, rows, mines) {
    this.cols = cols
    this.rows = rows
    this.mines = mines
  }

  drawGrid() {
    let grid = []
    for (let i = 0; i < this.rows; i++) {
      grid[i] = []
      for (let j = 0; j < this.cols; j++) {
        grid[i][j] = 0
      }
    }
    return grid
  }

  drawMine(grid) {
    this.mines.forEach(mine => {
      const [x, y] = mine
      grid[y][x] = '*'
    });
  }

  calculateProximity(grid) {
    this.mines.forEach(([col, row]) => {
      const neighbouringCells = this.findNeighbours(col, row)

      neighbouringCells.forEach(([col, row]) => {
        if (grid[row][col] !== '*') {
          grid[row][col] += 1
        }
      })
    })
  }

  findNeighbours(col, row) {
    let cells = [
      [col-1, row-1], [col, row-1], [col+1, row-1],
      [col-1, row],                 [col+1, row],
      [col-1, row+1], [col, row+1], [col+1, row+1]
    ]

    return cells.filter(([col, row]) => {
      return (row > -1 &&
        col > -1 &&
        row <= (this.rows - 1) &&
        col <= (this.cols -1)
      )
    })
  }

  changeZeroToDot(gridv) {
    grid.forEach((rowCells, rowIndex) => {
      rowCells.forEach((cell, colIndex) => {
        if (Number.isInteger(cell)) {
          if (cell == 0) {
            grid[rowIndex][colIndex] = '.'
          } else {
            grid[rowIndex][colIndex] = `${cell}`
          }
        }
      })
    })

  }

  showGrid() {
    let grid = this.drawGrid()
    if (this.mines && this.mines.length > 0) {
      this.drawMine(grid)
      this.calculateProximity(grid)
    }
    this.changeZeroToDot(grid)
    return grid
  }
}

module.exports = Minesweeper

minesweeper.test.js

const { expect } = require( 'chai' );
const Minesweeper = require( '../src/minesweeper' );

it('returns empty response', function () {
  const minesweeper = new Minesweeper(0, 0)
	expect( minesweeper.showGrid() ).to.eql( [] );
});

it('Empty mines return just dots', function () {
  const minesweeper = new Minesweeper(3, 2)
  expect(minesweeper.showGrid()).to.eql([
    ['.', '.', '.'],
    ['.', '.', '.']
  ] );
});

it('Has 1 mine for 3x2 grid', function () {
  const mines = [
    [1, 0]
  ]
  const minesweeper = new Minesweeper(3, 2, mines)

  expect(minesweeper.showGrid()).to.eql([
    ['1', '*', '1'],
    ['1', '1', '1']
  ] );
});

it('Has 1 mine for 5x3 grid', function () {
  const mines = [
    [0, 0],
    [1, 0],
    [1, 2]
  ]
  const minesweeper = new Minesweeper(5, 3, mines)

  expect(minesweeper.showGrid()).to.eql([
    ['*', '*', '1', '.', '.'],
    ['3', '3', '2', '.', '.'],
    ['1', '*', '1', '.', '.']
  ] );
});


it('Has 1 mine for 12x6 grid', function () {
  const mines = [
    [4, 3]
  ]
  const minesweeper = new Minesweeper(12, 6, mines)

  expect(minesweeper.showGrid()).to.eql([
    ['.', '.', '.', '.', '.', '.', '.', '.', '.', '.', '.', '.'],
    ['.', '.', '.', '.', '.', '.', '.', '.', '.', '.', '.', '.'],
    ['.', '.', '.', '1', '1', '1', '.', '.', '.', '.', '.', '.'],
    ['.', '.', '.', '1', '*', '1', '.', '.', '.', '.', '.', '.'],
    ['.', '.', '.', '1', '1', '1', '.', '.', '.', '.', '.', '.'],
    ['.', '.', '.', '.', '.', '.', '.', '.', '.', '.', '.', '.'],
  ] );
});