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Response Object

Response Object​

The res or response object is an instance of the Response class. It is used to send responses to the client. The res and response object has several methods to send different types of responses.

Note:

  • The res object is the second argument passed to the route handler function.
  • The response maybe referred to as res or response in the code examples.
res object
server.get('/', (request, response) => {
  response.send('Hello, World!');
});

methods​

res.send(data: string | object | Buffer | Stream | null | undefined)​

Sends a response to the client. The data parameter can be a string, object, Buffer, Stream, null, or undefined.

res.send example
server.get('/', (request, response) => {
  response.send('Hello, World!');
});

response.send can be used to send HTML.

res.send HTML example
server.get('/', (request, response) => {
  response.send('<h1>Hello, World!</h1>');
});

res.sendStatus(code: number)​

Sends a response with the specified status code. The code parameter is the status code to be sent.

res.sendStatus example
server.get('/', (request, response) => {
  response.sendStatus(200);
});

res.status(code: number)​

Sets the status code of the response. The code parameter is the status code to be set.

res.status example
server.get('/', (request, response) => {
  response.status(200).send('Hello, World!');
});

res.json(data: object)​

Sends a JSON response to the client. The data parameter must be an object.

res.json example
server.get('/', (request, response) => {
  response.json({ message: 'Hello, World!' });
});

Note: The res.json method automatically sets the Content-Type header to application /json.

res.sendFile(path: string)​

Sends a file in the response. The path parameter is the path to the file to be sent. It sets the Content-Type header based on the file extension. note: The path is relative to the root directory of the application. it does not send file as an attachment. for that use res.download method.

res.sendFile example
server.get('/', (request, response) => {
  response.sendFile('path/to/file.txt');
});

res.download(path: string, filename: string)​

Sends a file as an attachment with the specified filename. The path parameter is the path to the file to be sent, and the filename parameter is the name of the file to be sent.

res.download example
server.get('/', (request, response) => {
  response.download('path/to/file.txt', 'file.txt');
});