How to avoid internal server error without using try catch clause in node js?

Server.js file

var express = require('express');
var path = require('path');
var logger = require('morgan');
var bodyParser = require('body-parser');
var fs = require('fs');
var app = express();
var os = require('os');
//app.use(logger('dev'));
app.use(bodyParser.json());

app.all('/*', function (req, res, next) {
    // CORS headers
    res.header("Access-Control-Allow-Origin", "*"); // restrict it to the required domain
    res.header('Access-Control-Allow-Methods', 'GET,PUT,POST,DELETE,OPTIONS');
    // Set custom headers for CORS
    res.header('Access-Control-Allow-Headers', 'Content-type,Accept,X-Access-Token,X-Key');
    if (req.method == 'OPTIONS') {
        res.status(200).end();
    } else {
        next();
    }
});

// Auth Middleware - This will check if the token is valid
// Only the requests that start with /api/v1/* will be checked for the token.
// Any URL's that do not follow the below pattern should be avoided unless you
// are sure that authentication is not needed
//app.all('/api/v1/*', [require('./middlewares/validateRequest')]);
app.use('/', require('./routes')); // Write url in the routes.js file

app.use(function (err, req, res, next) {
    if (!err) {
        return next();
    }
    else {

            return next();

    }
});





// Start the server
app.set('port', process.env.PORT || 3000);

var server = app.listen(app.get('port'), function () {
    console.log('Express server listening on port ' + server.address().port);
});

I have read to handle internal server error Do like that. I even tried that too but it won't run as I wanted

if (app.get('env') === 'development') {
  app.use(function(err, req, res, next) {
    res.status(err.status || 500);
    console.log(err.message+'           w');
    res.render('error', {
      message: err.message,
      error: err
    });
  });
}

// production error handler
// no stacktraces leaked to user
app.use(function(err, req, res, next) {
  res.status(err.status || 500);
  res.render('error', {
    message: err.message,
    error: {}
  });
});

How to avoid that so that the server won't shot down ?

Tried that link too https://expressjs.com/en/guide/error-handling.html , http://code.runnable.com/UTlPPF-f2W1TAAEU/error-handling-with-express-for-node-js

via VIKAS KOHLI