etherpad-lite/src/node/hooks/express/errorhandling.js

const stats = require('ep_etherpad-lite/node/stats');

exports.expressCreateServer = function (hook_name, args, cb) {
  exports.app = args.app;

  // Handle errors
  args.app.use((err, req, res, next) => {
    // if an error occurs Connect will pass it down
    // through these "error-handling" middleware
    // allowing you to respond however you like
    res.status(500).send({error: 'Sorry, something bad happened!'});
    console.error(err.stack ? err.stack : err.toString());
    stats.meter('http500').mark();
  });

  return cb();
};