Describe the bug

when I use proxy with ws and bypass, server can't up

I tried [email protected] is ok, [email protected] is not ok and till now

Reproduction

https://stackblitz.com/edit/vitejs-vite-wuvxrc?file=vite.config.ts

Steps to reproduce

I create a new project use npm create vue
and set the base to '/aaa'
proxy / to a server , turn on ws: true, set bypass, and check the url is start of /aaa

import { fileURLToPath, URL } from 'node:url'

import { defineConfig } from 'vite'
import vue from '@vitejs/plugin-vue'
import vueJsx from '@vitejs/plugin-vue-jsx'

// https://vitejs.dev/config/
export default defineConfig({
  base: '/aaa',
  plugins: [vue(), vueJsx()],
  resolve: {
    alias: {
      '@': fileURLToPath(new URL('./src', import.meta.url))
    }
  },
  server: {
    host: '0.0.0.0',
    port: 9099,
    proxy: {
      '/': {
        target: 'http://10.0.0.230:5193',
        secure: false,
        ws: true,
        bypass(req, res, options) {
          console.log('1111 /bypass: ', req.url)
          if (req.url?.startsWith('/aaa')) {
            console.log('111111 bypass: ', req.url)
            return req.url // do not proxy
          }
        }
      }
    }
  }
})

npm run dev and open browser to visit

server restart quickly, below is some screenshot

System Info

System:
    OS: Windows 10 10.0.19045
    CPU: (12) x64 Intel(R) Core(TM) i5-10400 CPU @ 2.90GHz
    Memory: 4.46 GB / 23.84 GB
  Binaries:
    Node: 18.20.3 - C:\Program Files\nodejs\node.EXE
    npm: 10.7.0 - C:\Program Files\nodejs\npm.CMD
    bun: 1.1.25 - ~\.bun\bin\bun.EXE
  Browsers:
    Edge: Spartan (44.19041.1266.0), Chromium (127.0.2651.74)
    Internet Explorer: 11.0.19041.1566
  npmPackages:
    @vitejs/plugin-vue: ^5.0.5 => 5.1.2
    @vitejs/plugin-vue-jsx: ^4.0.0 => 4.0.1
    vite: ^5.4.2 => 5.4.2

Used Package Manager

npm

Logs

No response

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• The provided reproduction is a minimal reproducible example of the bug.