Sending response back to Client

In an Express.js application, you send a response back to the client using the res (response) object. The res object provides various methods to send different types of responses, such as text, JSON, HTML, and more. Here are some common ways to send responses back to the client:

1. Sending Plain Text:

   • Use the res.send method to send plain text.

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   app.get('/', (req, res) => {
     res.send('Hello, this is a plain text response!');
   });
   

2. Sending JSON:

   • Use the res.json method to send a JSON response.

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   app.get('/api/data', (req, res) => {
     const data = { message: 'This is a JSON response.' };
     res.json(data);
   });
   

3. Sending HTML:

   • Use the res.send method to send HTML content.

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   app.get('/html', (req, res) => {
     const htmlContent = '<h1>This is an HTML response</h1>';
     res.send(htmlContent);
   });
   

4. Redirecting:

   • Use the res.redirect method to redirect the client to a different URL.

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   app.get('/redirect', (req, res) => {
     res.redirect('/new-location');
   });
   

5. Sending Status Codes:

   • Use the res.status method to set the HTTP status code.

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   app.get('/not-found', (req, res) => {
     res.status(404).send('Page not found');
   });
   

6. Sending Files:

   • Use the res.sendFile method to send files.

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   const path = require('path');
   
   app.get('/file', (req, res) => {
     const filePath = path.join(__dirname, 'files', 'example.txt');
     res.sendFile(filePath);
   });
   

7. Setting Headers:

   • Use the res.set method to set HTTP headers.

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   app.get('/custom-header', (req, res) => {
     res.set('X-Custom-Header', 'Custom Header Value');
     res.send('Response with a custom header');
   });
   

These examples showcase various ways to send responses back to the client based on different scenarios. The res object provides a versatile set of methods to handle a wide range of response types. Depending on the use case, you can choose the appropriate method to send the desired response to the client.