React JS Library on Quickbase Dashboard

You can do all of the above.

There are widgets for web pages to add to dashboards.

Or you can make the code page be the home page for landing. 

Once to get into the coding its all possible.

Build your page using a code page pulling in any libraries from the CDN you need. Your code page named mypage.html will have a two different URLs similar to these:

https://SUBDOMAIN.quickbase.com/db/DBID?a=dbpage&pageID=4

https://SUBDOMAIN.quickbase.com/db/DBID?a=dbpage&pagename=mypage.html

Then on your dashboard create a Web Page Widget and configure it to use one of the above URLs. I almost always use the second form of the URL so I know what the page is named.

QuickBase will place your code page mypage.html inside an <iframe> on the dashboard. Note that if there are hyperlinks in your code page you will have to target them to parent as they will otherwise open within the <iframe>.

I know it's late, but this might be what you're looking for:
https://community.quickbase.com/quickbase/topics/react-js-in-quick-base