generator-express-no-stress/app/templates/server/api/middlewares/error.handler.js

Awesome APIs with ExpressJS and OpenAPI/Swagger: Features automatic request validation, interactive api doc, and more.

<% if (specification === 'openapi_3') { %>
// eslint-disable-next-line no-unused-vars, no-shadow
export default function errorHandler(err, req, res, next) {
  const errors = err.errors || [{ message: err.message }];
  res.status(err.status || 500).json({ errors })
}
<% } else { %>
// Error handler to display the error as HTML
// eslint-disable-next-line no-unused-vars, no-shadow
export default function errorHandler(err, req, res, next) {
  res.status(err.status || 500);
  res.send(
    `<h1>${err.status || 500} Error</h1>` +
    `<pre>${err.message}</pre>`);
}
<% } %>