Why does the process not exit when nodejs express throw?

  node.js, question

Today, I encountered a very strange problem, that is, when an exception is thrown in the code, the node process will not quit. the content of throw will be used as the content of pose, and cannot be captured through uncaughtException event. please give directions.

app.use(function(req,res,next){
 
 throw 'error';
 })

Express caught the exception in the outer catch and the process outputs the exception information to response.

The web framework certainly does not trust the user code. All calling user codes have try catch, so as to ensure the stability of the service.
In a single process and single thread environment like nodejs, an exception process will hang up.