/**
 * @param {number} numRows
 * @return {number[][]}
 */

var generate = function(numRows) {
    var oldRow = [];
    var newRow = [];
    var output = [[1]];
    function recurseFunc(previousRow, rowCount) {
        rowCount--;
        newRow = [1];
        if (rowCount === 0) {
            return output;
        } else {
            // console.log('old: ' + oldRow);
            for (let i = 0; i < oldRow.length - 1; i++) {
                newRow.push(oldRow[i] + oldRow[i+1])
            }
            newRow.push(1);
            // console.log('new: ' + newRow);
            oldRow = newRow;
            output.push(newRow);
            recurseFunc(oldRow, rowCount);
        }
    }
    recurseFunc(oldRow, numRows)
    return output;
};