med-plan-assistant/docs/README.dev-notes.md

Development Notes

Current Tech Stack (2025-11-26)

• React 19.1.1 with TypeScript 5.9.3
• shadcn/ui component library (Radix UI + Tailwind)
• Tailwind CSS 3.4.18 for styling
• Recharts 3.3.0 for data visualization
• Create React App 5.0.1 as build tool

Initial Setup (Fresh Clone)

# Install all dependencies
npm install

# Run development server
npm start

# Build for production
npm run build

shadcn/ui Setup (Already Done)

The project was set up with shadcn/ui components. If you need to add more components:

# Add new shadcn/ui components
npx shadcn@latest add [component-name]

# Example:
npx shadcn@latest add dialog

TypeScript Configuration

TypeScript is configured with:

• Strict mode enabled
• Path aliases: @/* → ./src/*
• Target: ES5
• Module: ESNext
• JSX: react-jsx

Tailwind CSS Configuration

Content paths in tailwind.config.js:

module.exports = {
  content: [
    "./src/**/*.{js,jsx,ts,tsx}",
  ],
  theme: {
    extend: {
      colors: {
        // HSL-based color system for shadcn/ui
      },
    },
  },
  plugins: [require("tailwindcss-animate")],
}

Global styles in ./src/styles/global.css:

@tailwind base;
@tailwind components;
@tailwind utilities;

@layer base {
  :root {
    --background: 0 0% 98%;
    --foreground: 222 47% 11%;
    /* ... more CSS variables for shadcn/ui theme */
  }
}

WSL Networking Issues

If access to http://localhost:3000 dose not work from Windows host, when running the React development server in WSL, look at the following troubleshooting steps.

Note that not all steps may be necessary, depending on your specific WSL and Windows setup.

In my case Option 1 (NAT, WSL default), cross-env host binding to HOST=0.0.0.0, port forwarding, and firewall rules were necessary to access the dev server from Windows host via http://172.20.39.187:3000 (my WSL IP address).

In my case the npm start terminal output shows:

  Local:            http://localhost:3000
  On Your Network:  http://172.20.39.187:3000

WSL Networking Modes

Check and potentially change the network mode of WSL.

Option 1: NAT Networking Mode (Default)

This is the default mode used if Option 2 is not specifically set. Unless the settings described in Option 2 are applied, this mode is active.

Option 2: Mirrored Networking Mode (Windows 11 22H2+)

In %USERPROFILE%\.wslconfig add:

[wsl2]
networkingMode=mirrored

Then stop WSL and start it again so the changes take effect:

wsl --shutdown
wsl

Dev Server Host Binding

To ensure that the React development server binds to all interfaces in WSL, install the cross-env package:

npm install cross-env --save-dev

And modify the start script in package.json as follows.

"scripts": {
  // "start": "react-scripts start"  // Original line, basic start command
  "start": "cross-env HOST=0.0.0.0 react-scripts start"
}

Note that when I tried it with only HOST=0.0.0.0 but without cross-env, even though some things may have changed, the server was still bound to 127.0.1.1 and not to all interfaces.

Port Forwarding

If you want to access the React dev server via http://localhost:3000 on Windows host, you need to set up port forwarding from Windows localhost to the WSL IP address.

First get the WSL IP address by running the following command in WSL:

hostname -I

Then use the WSL IP address (in my case 172.20.39.187) in the following command to set up permanent port forwarding.

# Add port forwarding rule
netsh interface portproxy add v4tov4 listenport=3000 listenaddress=127.0.0.1 connectport=3000 connectaddress=172.20.39.187

# In case you need to delete the rule later, use:
netsh interface portproxy delete v4tov4 listenport=3000 listenaddress=127.0.0.1

You should now be able to access the React dev server via http://localhost:3000 on Windows host, instead of having to use the WSL IP address.

Open Firewall Ports

In case you have trouble with your Windows Firewall blocking access to the forwarded port, or you want to allow access from other devices on your network, you may need to open the port in the firewall.

Run the following PowerShell commands to open the necessary port (just an example, ensure that the settings fit your security requirements):

# Open port 3000 for inbound TCP traffic on all network interfaces
New-NetFirewallRule -DisplayName "WSL React Dev Server" -Direction Inbound -Action Allow -Protocol TCP -LocalPort 3000

# Do the same but only for the WSL virtual network interface
New-NetFirewallRule -DisplayName "Allow WSL Inbound Port 3000" -Direction Inbound -Action Allow -Protocol TCP -LocalPort 3000 -InterfaceAlias "vEthernet (WSL (Hyper-V firewall))"

Just to rule out potential firewall issues, it is always an option to temporarily disable the firewall all together.

WARNING: IF YOU DO THIS, DO NOT FORGET TO RE-ENABLE THE FIREWALL AFTER TESTING!

Development Server

(Prevent) Auto Open in Browser

Per default, the React development server does automatically open the app in the browser when started. If this is not desired, add BROWSER=none to the start script in package.json as follows. Note that this also requires the cross-env package as described above.

"scripts": {
  "start": "cross-env HOST=0.0.0.0 BROWSER=none react-scripts start"
}

Alternatively (not verified) a .env file can be created in the project root with the following content, so no changes to package.json are necessary.

BROWSER=none

Hot Reloading File System Issues (in WSL)

Install development dependency nodemon to monitor file changes and restart the server automatically.

npm install -D nodemon

Modify the start script in package.json to use nodemon with polling enabled. This helps in environments like WSL where file system events may not be detected properly.

"scripts": {
  "start": "cross-env HOST=0.0.0.0 BROWSER=none CHOKIDAR_USEPOLLING=true react-scripts start"
}

Alternatively, add CHOKIDAR_USEPOLLING=true to a .env file in the project root:

echo CHOKIDAR_USEPOLLING=true >> .env

Then the start script can remain as:

npm start

Webhint

Setup webhint in Project

Check local config:

# Install hint locally in the project
npm install hint --save-dev

# Optionally use the web-recommended config
#npm install @hint/configuration-web-recommended --save-dev
#npm create hintrc

# Or create .hintrc manually with a basic config
```sh
cat > .hintrc <<EOL
{
  "extends": ["web-recommended"]
}
EOL

Add webhint script to package.json:

"scripts": {
  "webhint": "hint"
}

Optionally install puppeteer if you want to run webhint with headless Chrome:

npm install puppeteer --save-dev

Run webhint

Ensure that the React development server is running when you run webhint against http://localhost:3000.

npm start

Run webhint:

npm run webhint -- http://localhost:3000

Open ./hint-report/http-localhost-3000.html in a browser to see the report.

VS Code: Problems with "Microsoft Edge Tools for VS Code" Extension

Error message:

Unable to start webhint. Ensure you are using the latest version of the hint package.

Solution:

Install webhint locally in the project as shown above, or update to the latest version:

npm install hint@latest --save-dev

In doubt check the global installation and remove it if necessary:

# Global config
npm list -g hint

# Uninstall global version if necessary
npm uninstall -g hint

External Resources

• https://github.com/webhintio/hint
• https://webhint.io/docs/user-guide/configuring-webhint/summary/