pascals-triangle.js

/**
 * @param {number} numRows
 * @return {number[][]}
 */
const generate = numRows => {
  const res = [];

  for (let i = 0; i < numRows; i++) {
    const row = [1];

    for (let j = 1; j < i; j++) {
      row.push(res[i - 1][j - 1] + res[i - 1][j]);
    }

    if (i > 0) row.push(1);

    res.push(row);
  }

  return res;
};