Express res.end() Method

Posted in Express Tutorial

Updated on Feb 18, 2024

By Mari Selvan

👁️ 34 - Views

⏳ 4 mins

💬 1 Comment

Photo Credit to CodeToFun

🙋 Introduction

In the realm of web development using Node.js and Express.js, managing HTTP responses is a fundamental aspect.

The res.end() method plays a crucial role in finalizing and sending a response to the client.

In this guide, we'll explore the syntax, use cases, and best practices associated with the res.end() method in Express.js.

💡 Syntax

The syntax for the res.end() method is straightforward:

syntax.js

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res.end([data] [, encoding] [, callback])

data (Optional): A data parameter that can be a string or Buffer, representing the response body.
encoding (Optional): A string specifying the encoding for the data.
callback (Optional): A callback function that will be executed once the response has been sent.

❓ How res.end() Works

The res.end() method is used to quickly end the response process by sending data to the client. It can be called with or without data, and it signifies the end of the response stream.

example.js

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app.get('/hello', (req, res) => {
  res.end('Hello, World!');
});

In this example, the server responds to a GET request to '/hello' with the string 'Hello, World!' using res.end().

📚 Use Cases

Sending Plain Text:

The res.end() method is often used to send simple plain text responses to clients.
example.js
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```
app.get('/plaintext', (req, res) => {
  res.end('This is plain text response.');
});
```

Handling Empty Responses:

In this example, if a specific condition is met, the server responds with a 204 No Content status using res.status(204).end().

example.js

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app.get('/nocontent', (req, res) => {
  // Logic to handle a specific condition
  if (/* some condition */) {
    res.status(204).end();
  } else {
    // Other logic
    res.end('Data to be sent');
  }
});

🏆 Best Practices

Set Appropriate HTTP Status Codes:

Ensure that you set the appropriate HTTP status codes before calling res.end(). This communicates the outcome of the request to the client.
example.js
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```
app.get('/notfound', (req, res) => {
  res.status(404).end('Resource not found.');
});
```
Use res.send() for JSON Responses:

For JSON responses, consider using res.send() instead of res.end() as it automatically sets the 'Content-Type' header to 'application/json'.
example.js
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```
app.get('/json', (req, res) => {
  const jsonData = { message: 'This is a JSON response.' };
  res.send(jsonData);
});
```
Leverage res.end() for Binary Data:

When dealing with binary data, such as images or files, res.end() can be more appropriate.
example.js
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```
app.get('/image', (req, res) => {
  // Logic to read and send image binary data
  res.end(imageBinaryData, 'binary');
});
```

🎉 Conclusion

Understanding and effectively using the res.end() method in Express.js is key to crafting efficient and tailored responses in your web applications. Whether you're sending plain text or handling specific conditions, res.end() provides a flexible way to conclude the response cycle.

Now equipped with knowledge about the res.end() method, go ahead and optimize your Express.js applications for better response management!