发送整数值作为对 NodeJS API 调用的响应时未收到响应

Question

我试图在调用 API 端点后发送一些整数值作为响应。这是说明问题的示例代码：

app.post('/add5', (req, res) => {
  result = req.body.num + 5;
  res.send(result);
});

这是请求负载：

{
  "num": 7
}

预期输出：12

但是在终端中记录了以下输出并且没有收到（空白）响应。

RangeError [ERR_HTTP_INVALID_STATUS_CODE]: Invalid status code: 12
    at new NodeError (node:internal/errors:371:5)
    at ServerResponse.writeHead (node:_http_server:272:11)
    at ServerResponse._implicitHeader (node:_http_server:263:8)
    at ServerResponse.end (node:_http_outgoing:871:10)
    at ServerResponse.send (/storage/emulated/0/codes/api/node_modules/express/lib/response.js:221:10)
    at /storage/emulated/0/codes/api/index.js:208:7
    at Layer.handle [as handle_request] (/storage/emulated/0/codes/api/node_modules/express/lib/router/layer.js:95:5)
    at next (/storage/emulated/0/codes/api/node_modules/express/lib/router/route.js:137:13)
    at Route.dispatch (/storage/emulated/0/codes/api/node_modules/express/lib/router/route.js:112:3)
    at Layer.handle [as handle_request] (/storage/emulated/0/codes/api/node_modules/express/lib/router/layer.js:95:5)

但是，在字符串中添加一些字符串完全没问题。

app.post('/add5', (req, res) => {
  result = req.body.num + 5;
  res.send("Result: " + result);
});

这个returns预期输出即结果：12

Answer 1

使用res.json(result)或res.send(JSON.stringify(result))或res.send(200, result)。否则 express 假定 you're passing a http status code to send, as the error message signifies. Or upgrade to express 4, where this cannot happen any more.

发送整数值作为对 NodeJS API 调用的响应时未收到响应

no response received when sending integer value as response to NodeJS API call

javascript

api

response

node.js

express