rendezvous with cassidoo #187 - Interview question of the week

pascals.js

/**
 * From: https://buttondown.email/cassidoo/archive/5c50e780-c247-4167-a99d-99f4b9656011
 * @param {number} rowIndex Row index
 * @returns {number[]} Values in that row of Pascal’s Triangle.
 * @example
 * $ pascals(3)
 * -> [1, 3, 3, 1]
 */
function pascals (rowIndex) {
    let row = [1]
    for (let next = []; row.length <= rowIndex; row = next, next = [])
        for (let j = 0; j <= row.length; j++)
            next[j] = (row[j-1] || 0) + (row[j] || 0)
    return row
}