So I know this has been questioned quite a lot. To be exact for example in these questions:
I just had a jaw-drop moment - Termux allows you to install NodeJS on an Android device!
It seems to work for a basic Websocket Speed Test I had on hand. The http served by it can be accessed both locally and on the network.
There is a medium post that explains the installation process
Basically: 1. Install termux 2. apt install nodejs 3. node it up!
One restriction I've run into - it seems the shared folders don't have the necessary permissions to install modules. It might just be a file permission thing. The private app storage works just fine.