My Express server is sending a cookie to the client that is not httpOnly. Even so, the client doesn't have access to the cookie on document.cookie nor is the cookie showing up in the Application tab on chrome dev tools. However, I can see the cookie in Chrome settings Cookie and Site-data page. My original problem was trying to delete the cookie on the client side in the case the client becomes offline but I can't do that if I can't access the cookie in the first place.
On the server:
res.cookie("mycookie", "test", {httpOnly: false});
On the client
document.cookie
is undefined
Turns out the issue was with NGINX. www.mydomain.com and mydomain.com were both serving the same webpage. Cookies are tied to their domain and technically www.mydomain.com is different from mydomain.com. Added server blocks to my website config in NGINX to forward all traffic to www.mydomain.com to mydomain.com.