var generate = function(numRows) {
  var results = numRows === 0 ? [] : [[1]];
  if(numRows > 0) {
    for(let i = 0; i < numRows - 1; i++) {
      var tempArray = [];
      for(let j = 0; j <= i+1; j++) {
        tempArray.push(generateNum(results[i][j], results[i][j - 1]));
      }
      results.push(tempArray);
    }
  }
  return results;
};

var generateNum = function(i, j) {
  i = i || 0;
  j = j || 0;
  return i + j;
}