text: import { NotImplementedError } from '../extensions/index.js';
  
  /**
   * In the popular Minesweeper game you have a board with some mines and those cells
   * that don't contain a mine have a number in it that indicates the total number of mines
   * in the neighboring cells. Starting off with some arrangement of mines
   * we want to create a Minesweeper game setup.
   *
   * @param {Array<Array>} matrix
   * @return {Array<Array>}
   *
   * @example
   * matrix = [
   *  [true, false, false],
   *  [false, true, false],
   *  [false, false, false]
   * ]
   *
   * The result should be following:
   * [
   *  [1, 2, 1],
   *  [2, 1, 1],
   *  [1, 1, 1]
   * ]
   */
  export default function minesweeper (matrix) {
    let height = matrix.length;
    let length = matrix[0].length;
    let mines = 0;
    let mineField = [];
  
    for (let i = 0; i < height; i++) {
      mineField[i] = [];
      for (let j = 0; j < length; j++) {
        if (matrix[i - 1]) {
          if (matrix[i - 1][j - 1] == true) mines++; 
          if (matrix[i - 1][j] == true) mines++; 
          if (matrix[i - 1][j + 1] == true) mines++; 
        }
        if (matrix[i][j - 1] == true) mines++;
        if (matrix[i][j + 1] == true) mines++;
        if (matrix[i + 1]) {
          if (matrix[i + 1][j - 1] == true) mines++; 
          if (matrix[i + 1][j] == true) mines++; 
          if (matrix[i + 1][j + 1] == true) mines++; 
        }
        mineField[i][j] = mines;
        mines = 0;
      }
    }
  
    return mineField;
  }
  