Can't find static assets from express/npm module - express

Question

tldr;
My project is an NPM module that is used by an ExpressJS server. The server needs to specify an endpoint and my module will do the rest. How do I get my module to load the correct html page and grab the correct js/css files from the correct path?
The Problem
I'm running into a problem where I can see the directory structure of the site, using the serveIndex library, and all the files are in their correct directories but for some reason when I try to load any of the files, whether from the serveIndex view or from the actual endpoint where it should load, I get nothing but 404 errors.
Here's an example if someone wanted to use this NPM module from their project.
app.js (their server)
const express = require('express')
const { adminAreaConfig } = require('express-admin-area')
const app = express()
const adminArea = adminAreaConfig(express) // my module being passed the "express" library
app.use('/admin', adminArea) // specify a URL to use my module
app.listen(3000, () => console.log('\n\nServer Online\n\n'))
Here's an image of my projects dir structure after it's been built.
Going off of a console.log(__dirname), which returns <long path string>/express-admin-area/build/src, I then tell my module, using the express reference passed by the actual server in the code above, to look in the views directory with
... import libraries etc ...
const adminAreaConfig = express => {
const adminArea = express.Router()
adminArea.use('/', express.static(__dirname + '/views') // sets my modules views to the "http://localhost:3000/admin" path
adminArea.use('/dirs', serveIndex(__dirname)) // will get into this later
... some other stuff like exports etc ...
This then attempts to load the index.html file in the express-admin-area/build/src/views directory but fails because it can't locate the CSS and JS files inside express-admin-area/build/src/views/static/css or .../js.
First, I know it fails because instead of looking for http://localhost:3000/admin/static/css/styles.css it looks for http://localhost:3000/static/css/styles.css, so that's another problem I need to solve entirely.
Second, looking back at the small code sample above, adminArea.use('/dirs', serveIndex(__dirname)), I'm using the serveIndex library in an attempt to view the directory structure. If I go to http://localhost:3000/admin/dirs I get the correct directories and files in the browser
But now, if I try to view an actual file I'm met with the error Cannot GET /admin/dir/main.js for example if I were to go to http://localhost:3000/admin/dir/main.js, but I can continue going deeper in the directories if I wanted such as the controllers or routes directories from the image.
What I want
I need a way to get these static assets to load. If I point my module to a basic html page with a simple <h1>Hello, World!</h1> then that's what Ill get but trying to load any outside scripts/stylesheets is when I get the 404 errors and nothing loads.

Answer 1

I'll be answering my own question.
The solution is actually pretty simple. The view layer of this module is handled by React, CRA to be specific. CRA will look for some specific environment variables, one of them being PUBLIC_URL. All I had to do was
Create a .env file in the root directory of my CRA
add PUBLIC_URL="/admin"
Afterward, it's just rebuilding the project, yarn build, and reset the server. CRA will then look at http://localhost:3000/admin/static/... instead of http://localhost:3000/static/... for static assets.