节点express.js响应post请求

Question

我有一个客户端react应用程序，它将一些信息发布到node express后端，并且正在等待客户端的响应。我的服务器侧代码是：

server.post('/api/verify-valid-email', (req : express.Request, res :
express.Response, next) => {

    const body = JSON.parse(req.body)

    if (body && body.email) {

        const email = body.email

        res.set('Content-Type', 'application/JSON')
        res.send(JSON.stringify({ validEmail: true }))

    } else {

        res.set('Content-Type', 'application/JSON')
        res.send(JSON.stringify({ validEmail: false }))


    }

    res.redirect('/home');

})

在客户端我有

callApi = async () => {

    const res = await fetch( '/api/verify-valid-email, {                
         method  : 'POST',
         headers : {
            'Accept'      : 'application/JSON',
            'Content-Type': 'application/JSON',
          },
          mode: 'no-cors',
          body: JSON.stringify({
            email: 'xxx@gmail.com'
         })
    })

    const body = await res.json();

    return body
}

当前，代码正在抛出错误：can't set headers after they are set

error: _http_outgoing.js:356
    throw new Error('Can\'t set headers after they are sent.');
    ^

Error: Can't set headers after they are sent.
    at ServerResponse.OutgoingMessage.setHeader (_http_outgoing.js:356:11)
    at ServerResponse.header (/Users/lingxiao/Documents/Career/spice.ai/server/functions/node_modules/express/lib/response.js:767:10)
    at Object.email_verifier.verify [as callback] (/Users/lingxiao/Documents/Career/spice.ai/server/functions/lib/index.js:42:21)
    at callback (/Users/lingxiao/Documents/Career/spice.ai/server/node_modules/email-verify/index.js:154:19)
    at Socket.<anonymous> (/Users/lingxiao/Documents/Career/spice.ai/server/node_modules/email-verify/index.js:239:5)
    at Socket.g (events.js:292:16)
    at emitNone (events.js:91:20)
    at Socket.emit (events.js:185:7)
    at endReadableNT (_stream_readable.js:974:12)
    at _combinedTickCallback (internal/process/next_tick.js:80:11)

是否可以在邮件中发送回复？它是自然做的，是吗？如果我想将JSON发送回客户端，正确的API是什么？

Answer 1

你需要

 return res.send() 

或

 return res.redirect()

在服务器端结束执行