// attrs

  BASE: {

    grid_size: 8,

    num_mines: 8,

  },

​

  EASY: { grid_size: 8, num_mines: 8 },

  MEDIUM: { grid_size: 16, num_mines: 24 },

  HARD: { grid_size: 32, num_mines: 100 },

  EXPERT: { grid_size: 64, num_mines: 300 },

};

​

// visible state of grid

GRID_STATE = {

  COVERED: 0, // not checked, blank square

  FLAGGED: 1, // flagged as mine

  QUESTION: 2, // unsure

  CLEAR: 3, // opened by user

};

​

// draw colors

COLORS = {};

COLORS[GRID_STATE.COVERED] = "#aaaaaa";

COLORS[GRID_STATE.QUESTION] = "#aaaaaa";

COLORS[GRID_STATE.FLAGGED] = "#aaaaaa";

COLORS[GRID_STATE.CLEAR] = "#eeeeee";

COLORS.HOVER = "#cccccc";

​

// cell directions

DIRECTIONS = [

  { c: -1, r: -1 },

  { c: 0, r: -1 },

  { c: 1, r: -1 }, 

  { c: -1, r: 0 },

  { c: 1, r: 0 }, 

  { c: -1, r: 1 },

  { c: 0, r: 1 },

  { c: 1, r: 1 }, 

];

​