JSX Tool Dev Server

A lightweight development server that bridges your browser and filesystem for real-time React component editing

Documentation • Examples Repository

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Overview

JSX Tool Dev Server enables the JSX Tool Chrome extension to read and modify your React source code in real-time. It provides a WebSocket server scoped to your project directory, allowing secure file system access from the browser extension.

For example integrations, check out the jsx-tool-examples repository which demonstrates various setups including React Router with Vite, Next.js, and more.

Quick Start

Vite Projects

For Vite projects, use the plugin-based approach:

# Install
npm i @jsx-tool/jsx-tool

# Add to vite.config.ts
import { jsxToolDevServer } from "@jsx-tool/jsx-tool/vite";

export default defineConfig({
  plugins: [
    react(),
    jsxToolDevServer(),
  ],
});

Non-Vite Projects

For non-Vite projects, use the CLI with optional proxy:

# Initialize configuration
npx @jsx-tool/jsx-tool init

# Start dev server (with proxy)
npx @jsx-tool/jsx-tool start

# Or start without proxy
npx @jsx-tool/jsx-tool start --no-proxy

CLI API

init

Initialize JSX Tool configuration in your project. Call this from next to your package.json. !!!not your root package.json if a monorepo!!!

npx @jsx-tool/jsx-tool init [options]

Options:

• -f, --from <path> - Working directory (default: current directory)

Interactive prompts:

• Vite project detection
• Server port configuration
• Proxy enablement
• WebSocket port setup

Creates:

• .jsxtool/rules.md - Custom prompting rules (all projects)
• .jsxtool/config.json - Configuration file (non-Vite only)

start

Start the JSX Tool development server.

npx @jsx-tool/jsx-tool start [options]

Options:

Working Directory:

• -f, --from <path> - Working directory (default: current directory)
• --node-modules-dir <path> - node_modules directory (auto-detected or defaults to working directory)
• --additional-directories <paths> - Comma-separated list of additional directories to watch

Server Configuration:

• --server-port <port> - Target server port (default: 4000)
• --server-host <host> - Target server host (default: localhost)
• --server-protocol <protocol> - Target server protocol: http or https (default: http)

Proxy Configuration:

• --proxy-port <port> - Proxy server port (default: 3000)
• --proxy-host <host> - Proxy server host (default: localhost)
• --proxy-protocol <protocol> - Proxy server protocol: http or https (default: http)
• --no-proxy - Disable proxy server

WebSocket Configuration:

• --ws-port <port> - WebSocket server port (default: 12021)
• --ws-host <host> - WebSocket server host (default: localhost)
• --ws-protocol <protocol> - WebSocket protocol: ws or wss (default: ws)

Development Options:

• --insecure - Run dev server without signature check
• --logging - Enable logging
• -d, --debug - Enable debug logging

Examples:

# Start with default settings (reads from .jsxtool/config.json)
npx @jsx-tool/jsx-tool start

# Start without proxy
npx @jsx-tool/jsx-tool start --no-proxy

# Start with custom ports
npx @jsx-tool/jsx-tool start --server-port 3000 --proxy-port 4000

# Start in monorepo with explicit node_modules path
npx @jsx-tool/jsx-tool start --node-modules-dir ../../node_modules

# Start with additional directories to watch
npx @jsx-tool/jsx-tool start --additional-directories packages/ui,packages/shared

# Start with debug logging
npx @jsx-tool/jsx-tool start --debug

Vite Plugin API

For Vite projects, use the jsxToolDevServer plugin instead of the CLI.

import { defineConfig } from "vite";
import react from "@vitejs/plugin-react";
import { jsxToolDevServer } from "@jsx-tool/jsx-tool/vite";

export default defineConfig({
  plugins: [
    react(),
    jsxToolDevServer({
      debug: false,                    // Enable debug logging
      nodeModulesDir: undefined,       // Path to node_modules (auto-detected)
      additionalDirectories: []        // Additional directories to watch (for mono-repos)
    }),
  ],
});

Plugin Options:

• debug?: boolean - Enable debug logging (default: false)
• nodeModulesDir?: string - Explicit path to node_modules directory (auto-detected by default)
• additionalDirectories?: string[] - Additional directories to watch relative to project root

What it does:

• Automatically starts WebSocket server with your Vite dev server
• Injects client script during development only
• Configures WebSocket URL based on Vite's server settings
• No proxy needed - works directly with Vite's dev server

Monorepo setup:

Install @jsx-tool/jsx-tool in your app package (not monorepo root) and add the plugin to that app's vite.config.ts. The plugin will auto-detect the root node_modules directory.

Configuration File

For non-Vite projects, create .jsxtool/config.json:

{
  "serverPort": 3000,
  "serverHost": "localhost",
  "serverProtocol": "http",
  "noProxy": false,
  "proxyPort": 4000,
  "proxyHost": "localhost",
  "proxyProtocol": "http",
  "wsPort": 12021,
  "wsHost": "localhost",
  "wsProtocol": "ws",
  "injectAt": "</head>"
}

Configuration priority:

1. CLI options (highest priority)
2. Config file values
3. Default values (lowest priority)

Custom Prompting Rules

Create .jsxtool/rules.md to add project-specific prompting rules that will be included when using the JSX Tool extension:

# Project Rules

- Always use TypeScript
- Follow the existing component structure in src/components
- Use Tailwind CSS for styling

System Architecture

Components

1. Browser Extension - Receives the WebSocket address and connects to the JSX Tool dev server
2. JSX Tool WebSocket Server - Lightweight server scoped to your React project for secure file operations
3. Your Project Web Server - Communicates the WebSocket address either manually or via proxy
4. JSX Tool Proxy Server (optional) - Intercepts document requests to inject the WebSocket address

How It Works

With Vite:

• Plugin starts WebSocket server alongside Vite dev server
• Client script is automatically injected during development
• Extension connects directly to your dev server

Without Vite (using proxy):

• Proxy intercepts HTTP requests to your dev server
• Injects WebSocket connection script into HTML responses
• WebSocket server handles file system operations
• Extension connects via injected script

Without Vite (no proxy):

• Manually add WebSocket connection script to your HTML
• WebSocket server handles file system operations
• Extension connects via your script

Security

• File system scope - Server only accesses files within your project directory and configured additional directories
• Development only - Designed for local development environments
• Signature verification - Optional signature checking for enhanced security (disable with --insecure)

Troubleshooting

Vite Projects

"Cannot find module @jsx-tool/jsx-tool/vite"

• Ensure @jsx-tool/jsx-tool is installed in the same workspace/package as your vite.config.ts

Extension can't connect

• Confirm Vite dev server is running
• Check that JSX Tool extension is enabled in Chrome
• Verify no firewall blocking WebSocket connections

Non-Vite Projects

"Invalid working directory" errors

• Ensure React is installed in your project
• For monorepos, use --node-modules-dir to point to the correct node_modules (not common)

Proxy connection issues

• Verify your app server is running on the configured port
• Check proxy and server ports don't conflict
• Ensure serverPort matches your app's port

WebSocket connection fails

• Check WebSocket port isn't blocked by firewall
• Verify no other service is using the WebSocket port
• Try with --debug flag to see detailed logs

Examples

See the jsx-tool-examples repository for complete working examples:

• React Router with Vite
• Next.js integration
• Custom webpack setups
• Monorepo configurations

Documentation

For complete documentation, visit jsxtool.com/docs/dev-server

Linux Clipboard Support

Ubuntu/Debian

sudo apt-get install xclip

Fedora/RHEL

sudo dnf install xclip