I encounter an endlessly processing request once this code is added

Question

I have no clue why this piece of code prevents my API from working properly. It causes all requests to process endlessly and if I remove it - everything works fine

app.use((req, res, next) => {
  res.setHeader("Access-Control-Allow-Origin", "*");
  res.setHeader("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept, Authorization");
  res.setHeader("Access-Control-Allow-Methods", "GET, POST, PATCH, DELETE");
});

Answer 1

There's no call to next() so the request gets hung up here. It doesn't advance to other request handlers (that's what next() does) and it doesn't send a response so the request just dies there and will probably eventually timeout. Add next() like this:

app.use((req, res, next) => {
  res.setHeader("Access-Control-Allow-Origin", "*");
  res.setHeader("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept, Authorization");
  res.setHeader("Access-Control-Allow-Methods", "GET, POST, PATCH, DELETE");
  next();
});