Unique Paths (Iterative)

let uniquePaths = function(m, n) {

    let getKey = (row, col) => `${row}${col}`;

    let cache = { }
    for (let row = 1; row <= m; row++) {
        for (let col = 1; col <= n; col++) {
            if (row === 1) {
                cache[getKey(row, col)] = 1;
            }
            else if (col === 1) {
                cache[getKey(row, col)] = 1;
            }
            else {
                cache[getKey(row, col)] = cache[getKey(row-1, col)] + cache[getKey(row, col - 1)];
            }
        }
    }

    return cache[getKey(m,n)];
};