foo?.bar;

a?.b.c?.d.e;

a.b?.c.d?.e;

a.b.c?.d?.e;

orders?.[0].price;

orders?.[0]?.price;

orders[client?.key].price;

orders[client.key]?.price;

(0, a?.b).c;

(0, (0, a?.b).c?.d).e;