sudoku-validator

sudoku-validator.js

function getIndex(i) {
  return Math.floor(i / 3);
}

function fillArray(len, item) {
  return new Array(len).fill(item);
}

function isValid(totals) {
  const result = Object.values(totals).every(total => {
    return total.flat().every(value => value === 45);
  });

  return result;
}

function sudokuReducer(sums, row, i) {
  return row.reduce((sums, value, j) => {
    sums.rows[i] += value;
    sums.cols[j] += value;
    sums.grids[getIndex(i)][getIndex(j)] += value;

    return sums;
  }, sums);
}

function validate(board) {
  const sums = {
    rows: fillArray(9, 0),
    cols: fillArray(9, 0),
    grids: [[0, 0, 0], [0, 0, 0], [0, 0, 0]],
    // grids: fillArray(3, fillArray(3, 0)),
  };

  const reducedBoard = board.reduce(sudokuReducer, sums);

  return isValid(reducedBoard);
}