Error sending express http response after request to database?

Question

JavaScript

Colleagues, hello.
There is such a controller (it makes no sense, just indicative).

async register(req, res) {
    
    try {
      
      await UserModel.findAll();
      console.log('THIS');
      res.send('THIS');
    }catch (e) {
      res.send('ERROR');
      console.log('ERROR CATCHING');
    }

When requesting through sikalize to the database, if you make a call to the findAll function through await, we get the following error

spoiler

node:internal/process/promises:245
triggerUncaughtException(err, true /* fromPromise */);
^

Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client
at new NodeError (node:internal/errors:329:5)
at ServerResponse.setHeader (node:_http_outgoing:573:11)
at ServerResponse.header (/Users/denisdavydov/Desktop/espp_service/node_modules/express/lib/response.js:771:10)
at ServerResponse.send (/Users/denisdavydov/Desktop/espp_service/node_modules/express/lib/response.js:170:12)
at register (/Users/denisdavydov/Desktop/espp_service/controller/User.js:31:11)
at processTicksAndRejections (node:internal/process/task_queues:94:5) {
code: 'ERR_HTTP_HEADERS_SENT'

It's like something implicitly already set the title. If you make a request synchronously, then the response is sent to the client. The request itself fulfills, console.log after it fulfills (displays THIS), but res.send("THIS") already crashes with the above error. What could be the problem?

Answer 1

Issue resolved. By my own stupidity, in the middleware, when checking the connection to the database, I called next () twice