vite-plugin-ssr-hot-reload.ts

import { ServerResponse } from 'node:http'

function ssrHotReload(): Plugin {
  return {
    name: 'vite-plugin-ssr-hot-reload',
    apply: 'serve',
    configureServer(server) {
      const injectScript = `<script type="module" src="/@vite/client"></script>`

      server.middlewares.use((req, res, next) => {
        let buffer = ''

        const originalWrite = res.write.bind(res) as ServerResponse['write']
        const originalEnd = res.end.bind(res) as ServerResponse['end']

        res.write = ((chunk: any) => {
          buffer += chunk.toString()
          return true
        }) as typeof res.write

        res.end = ((chunk: any) => {
          if (chunk) {
            buffer += chunk.toString()
          }

          const contentType = res.getHeader('content-type') || ''
          if (typeof contentType === 'string' && contentType.includes('text/html')) {
            buffer += `\n${injectScript}\n`
            res.setHeader('content-length', Buffer.byteLength(buffer))
          }

          originalWrite(buffer)
          originalEnd()
        }) as typeof res.end

        next()
      })
    },
    handleHotUpdate: ({ server, modules }) => {
      const isSSR = modules.some((mod) => mod._ssrModule)
      if (isSSR) {
        server.hot.send({ type: 'full-reload' })
        return []
      }
    }
  }
}