HTML Code

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>Pascal triangle return array</title>
</head>
<body>
  <h1>Return Pascal's triangle as nested arrays</h1>
  <p>Edit <code>numRows</code>, then <strong>Run</strong>.</p>
  <pre id="out"></pre>
  <script>
    (function () {
      function generate(numRows) {
        if (numRows < 1) {
          return [];
        }
        var triangle = [];
        var i;
        var j;
        for (i = 0; i < numRows; i++) {
          var row = new Array(i + 1).fill(1);
          for (j = 1; j < i; j++) {
            row[j] = triangle[i - 1][j - 1] + triangle[i - 1][j];
          }
          triangle.push(row);
        }
        return triangle;
      }
      var numRows = 5;
      document.getElementById("out").textContent = JSON.stringify(generate(numRows));
    })();
  </script>
</body>
</html>

Lines: 0 | Characters: 0

Live Preview Auto-refresh on Run

JavaScript Pascal's Triangle — Return Array of Rows (Try It)