codewars sudoku

var Sudoku = function(data) 
{
  //   Private methods
  // -------------------------

  function makeColArr() {
    let columns = [];
    let valid = true;
    data.forEach((row, rowIndex) => {
      columns.push([]);
      row.forEach((cell, cellIndex) => {
        const colRow = data[cellIndex];
        const colCell = row[rowIndex];
        if(!cell) {
          valid = true;
          return;
        }
        columns[rowIndex].push(cell);
      });
    });
    return valid ? columns: null;
  }

  //   Public methods
  // -------------------------
  return {
    isValid: function() {
      let rowsValid = true;
      let columnsValid = true;
      const columns = makeColArr();
      if(!columns) {
        return false;
      }
      data.forEach((row, rowIndex) => {
        row.forEach((cell, cellIndex) => {
          column = columns[cellIndex];
          rowsValid = row && row.indexOf(cellIndex) > -1;
          columnsValid = column && column.indexOf(cellIndex) > -1;
        });
      });
      return rowsValid;
    }
  };
};