remix-express-dev-server

This package is a Vite plugin that loads your Express app in development. It expects the app to have been created in your entry.server.tsx file via the createExpressApp help.

Installation

Install the following npm package:

npm install -D remix-express-dev-server

Configuration

Add the Vite plugin to your vite.config.ts file. Also, configure build.target='esnext' to support top-level await.

import { expressDevServer } from 'remix-express-dev-server'
import { vitePlugin as remix } from '@remix-run/dev'
import { defineConfig } from 'vite'
import tsconfigPaths from 'vite-tsconfig-paths'

export default defineConfig({
  build: {
    target: 'esnext',
  },
  plugins: [
    expressDevServer(), // add expressDevServer plugin
    remix(),
    tsconfigPaths(),
  ],
})

Options

The expressDevServer plugin also accepts options:

export type DevServerOptions = {
  entry?: string // Express app entry: default = 'virtual:remix/server-build'
  entryName?: string // name of express app export: default = app
  appDirectory?: string // path to remix app directory: default = ./app
  configureServer?: (server: http.Server) => void // allow additional configuration
  // of Vite dev server (like setting up socket.io)
}

Package.json

The scripts for dev and build have been simplified.

Update scripts in your package.json file. For development, Vite will handle starting express and calling Remix to build your app, so simply call vite.

For building, Remix will build your app and create the server and client bundles. The server bundle is in ./build/server/index.js

To run your production build, call node ./build/server/index.js

Make sure to set NODE_ENV=production, otherwise it will not create your server.

{
  "scripts": {
    "dev": "vite",
    "build": "remix vite:build",
    "start": "NODE_ENV=production node ./build/server/index.js"
  }
}

Advanced configuration

Socket.io

You can wrap the Vite dev server with the socket.io server.

NOTE: configureServer is only called for development. In production, use the createExpressApp({ createServer }) function to initialize socket.io. You can import same init function in both places.

// vite.config.ts
export default defineConfig({
  plugins: [
    expressDevServer({
      configureServer(server) {
        const io = new Server(server)

        io.on('upgrade', async (req, socket, head) => {
          console.log(
            `Attemping to upgrade connection at url ${
              req.url
            } with headers: ${JSON.stringify(req.headers)}`,
          )

          socket.on('error', err => {
            console.error('Connection upgrade error:', err)
          })

          console.log(`Client connected, upgrading their connection...`)
        })
        io.on('connection', socket => {
          console.log('Client connected')
          socket.emit('server', 'hello from server')
          socket.on('client', data => {
            console.log('Client sent:', data)
            socket.emit('server', data)
          })
          socket.on('disconnect', () => {
            console.log('Client disconnected')
          })
        })
      },
    }),
    // ...
  ],
})