What is the Response Object?

This is the object that is often abbreviated to res. This object includes a set of helper methods that can improve developer experience and also increase the speed of creating new API endpoints.

The Server Response Object Helpers

• res.status(code): This is a function that sets the status code.

• code: must be a valid HTTP status code.

• res.json(body): This sends a JSON response.

  • body must be a serializable object.

• res.send(body): This sends the HTTP response.

  • body can be a string, an object or a Buffer

• res.redirect([status,], path): This redirects you to a specific path or a URL.

  • status has to be a valid HTTP status code.

  • If nothing is specified, status will default to "307" "Temporary redirect"

Setting the status code of a response

You can set a status code of the response you send back to the client.

Example code:

export default function handler(req, res) {
  res.status(200).json({ message: 'Hello from Next.js!' })
}

• The status code of the response is set to `200` which means `OK`.- It returns a `message` property which has `'Hello from Next.js!'` as its value in the JSON response.

Sending a JSON Response

Like mentioned above, you can send a JSON message back with your response to the client. This response, however, must be a serialized object.

You might want to let the client know the status of the request depending on the result of the requested endpoint.

Example:

export default async function handler(req, res) {
  try {
    const result = await someAsyncOperation()res.status(200).json({ result })
  } 
  catch (err) {res.status(500).json({ error: 'failed to load data' })}}

• JSON response with the status code `200` is sent together with the result of the async operation.

• It is contained in a try catch block to handle errors that might occur.

• The appropriate status code and error message are caught and sent back to the client.

Sending an HTTP response

This works the same way as sending a JSON response, but the difference is that the response body can be a 'string', 'object' or a 'Buffer'.

Example:

export default async function handler(req, res) {
  try {
    const result = await someAsyncOperation()res.status(200).send({ result })
  } 
  catch (err) {res.status(500).send({ error: 'failed to fetch data; })}}

Redirects to a specified path or URL

Let's say you want to redirect your client to a specified path or URL once something changes. A good example can be a form, where you change the path or URL once the form is submitted.

Example:

export default async function handler(req, res) {
  const { name, message } = req.body
  try {await handleFormInputAsync({ name, message })res.redirect(307, '/')} 
  catch (err) {res.status(500).send({ error: 'failed to fetch data' })}}

The clients gets redirected to the / path if the form is successfully submitted.