indexHtml

export function indexHtmlMiddleware(
  server: ViteDevServer
): Connect.NextHandleFunction {
  return async (req, res, next) => {
    // 抹除 query 信息 和 hash 信息的纯 url
    const url = req.url && cleanUrl(req.url)
    // spa-fallback always redirects to /index.html
    // 如果请求的是 html 资源，同时 header.sec-fetch-dest 不是通过 script 发起的资源请求，则处理并返回
    if (url?.endsWith('.html') && req.headers['sec-fetch-dest'] !== 'script') {
      const filename = getHtmlFilename(url, server)
      if (fs.existsSync(filename)) {
        try {
          let html = fs.readFileSync(filename, 'utf-8')
          html = await server.transformIndexHtml(url, html)
          return send(req, res, html, 'html')
        } catch (e) {
          return next(e)
        }
      }
    }
    next()
  }
}