204 No Content in Rest API - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the HTTP status code returned?

You send a DELETE request to remove a resource from a REST API. The server successfully deletes the resource but returns no content in the response body.

What HTTP status code should the server return?

A 200 OK

B 204 No Content

C 404 Not Found

D 500 Internal Server Error

💡 Hint

Think about a status code that means success but no response body.

204 No Content means the request was successful but the server has no content to return. It is commonly used for DELETE requests.

🧠 Conceptual

intermediate

Why use 204 No Content instead of 200 OK with empty body?

When a REST API successfully processes a request but has no content to return, why is 204 No Content preferred over 200 OK with an empty response body?

A 200 OK causes the client to retry the request automatically.

B 200 OK is only for GET requests, so it cannot be used here.

C 204 No Content allows caching, 200 OK does not.

D 204 No Content explicitly tells the client there is no body, so it can skip parsing.

💡 Hint

Think about how clients handle response bodies.

204 No Content tells clients explicitly that there is no response body, so clients can avoid unnecessary parsing or rendering.

❓ Predict Output

advanced

What is the output of this Express.js code?

Consider this Node.js Express server code snippet:

app.delete('/item/:id', (req, res) => {
  // Assume item is deleted successfully
  res.status(204).send();
});

What will the client receive as the HTTP status and body?

Rest API

app.delete('/item/:id', (req, res) => {
  // Assume item is deleted successfully
  res.status(204).send();
});

A Status 204 with empty body

B Status 204 with JSON body {"message":"Deleted"}

C Status 200 with empty body

D Status 404 with error message

💡 Hint

Check what res.status(204).send() does.

Setting status 204 and calling send() sends a response with status 204 and no content in the body.

🔧 Debug

advanced

Why does this API client fail to handle 204 response?

This JavaScript fetch client code tries to parse JSON from a 204 No Content response:

fetch('/api/delete/123', { method: 'DELETE' })
  .then(res => res.json())
  .then(data => console.log(data))
  .catch(err => console.error('Error:', err));

What error will occur and why?

Rest API

fetch('/api/delete/123', { method: 'DELETE' })
  .then(res => res.json())
  .then(data => console.log(data))
  .catch(err => console.error('Error:', err));

A SyntaxError because response body is empty and cannot be parsed as JSON

B TypeError because fetch does not support DELETE method

C ReferenceError because 'res' is undefined

D No error, logs empty object

💡 Hint

Think about parsing empty response as JSON.

Calling res.json() on an empty response body causes a SyntaxError because there is no JSON to parse.

🚀 Application

expert

How to correctly handle 204 No Content in a React app fetch call?

You make a DELETE request in a React app using fetch. The server returns 204 No Content. You want to update the UI after deletion without errors.

Which code snippet correctly handles the 204 response?

A

fetch('/api/item/1', { method: 'DELETE' })
  .then(res => {
    if (res.ok) return res.json();
  })
  .then(data => updateUI(data));

B

fetch('/api/item/1', { method: 'DELETE' })
  .then(res => res.json())
  .then(data => updateUI(data));

C

fetch('/api/item/1', { method: 'DELETE' })
  .then(res => {
    if (res.status === 204) return null;
    return res.json();
  })
  .then(data => {
    if (data !== null) updateUI(data);
    else updateUI(null);
  });

D

fetch('/api/item/1', { method: 'DELETE' })
  .then(res => res.text())
  .then(text => updateUI(text));

💡 Hint

Check how to avoid parsing JSON when no content is returned.

Option C checks for 204 status and returns null instead of calling res.json(), avoiding parsing errors. Then it updates UI accordingly.