Pascal Triangle

let generate = function(numRows) {

    if (numRows === 0) return [];

    let result = [];
    for (let i = 1; i <= numRows;i++) {
        let row = [];
        for (let j = 0; j < i; j++) {
            if (j === 0 || j === i - 1) {
                row[j] = 1;
            }
            else {
                row[j] = result[i - 2][j - 1] + result[i - 2][j];
            }
        }
        result.push(row);
    }

    return result;
};