Response Helpers

Kaelum provides an optional, opt-in middleware to enrich the Express Response (res) object with semantic helper methods.

Instead of writing boilerplate Express code (res.status(200).json(...)), you can use clean, readable shortcuts inspired by modern frameworks.

Why use Response Helpers?

• Semantic readability: res.notFound() is easier to understand at a glance than res.status(404).send().
• Automatic Content-Type: Passing a string automatically sends text/html, while passing an object or array sends application/json.
• Standardized Error Formatting: Error methods (400-500) automatically format string messages into a structured JSON payload: { "error": "Message" }.

Enabling the Feature

To prevent conflicts with other Express middleware you might be using, Response Helpers are opt-in. You must enable them globally:

const kaelum = require('kaelum');
const app = kaelum();

// Enable the helpers
app.useResponseHelpers();

app.get('/users/:id', (req, res) => {
  const user = db.find(req.params.id);

  if (!user) {
    // 404 Not Found -> { "error": "User not found" }
    return res.notFound("User not found");
  }

  // 200 OK -> JSON payload
  return res.ok(user);
});

Available Methods

Once enabled, the following methods are attached to res:

Method	HTTP Status	Use Case
res.ok(data)	200	Successful query or operation
res.created(data)	201	Resource successfully created
res.noContent()	204	Successful operation, no body to return
res.badRequest(err)	400	Validation failed, malformed request
res.unauthorized(err)	401	Missing or invalid authentication
res.forbidden(err)	403	Authenticated, but lacks permissions
res.notFound(err)	404	Resource does not exist
res.conflict(err)	409	Resource already exists or state conflict
res.error(err, status)	Custom / 500	Server error or custom status code

See the useResponseHelpers() API Reference for technical details.