I have this:
map = ranks.map((row, r) => ( row.map((rank, i) => { return [element(r, i, state, rank, toggled, onClick)]; }) ));
simplify answer above
const array = ['apple','orange','banana']; array.map((element, index) => (index === array.length - 1) ? \`${element}.\` : \`${element},\`);