[Solved] Identify the error in this Node.js code that tries to set a response header: const http = require('http'); const server = http.createServer((req, res) => { res.write('Hello'); res.... | Node.js

Node.js - HTTP Module

Identify the error in this Node.js code that tries to set a response header:

const http = require('http');
const server = http.createServer((req, res) => {
  res.write('Hello');
  res.setHeader('Content-Type', 'text/plain');
  res.end();
});
server.listen(3000);

Ares.end() is missing a parameter

BThe method setHeader does not exist on res

CHeaders must be set before writing the response body

DThe server.listen port number is invalid

Step-by-Step Solution

Solution:

Step 1: Check order of header setting and response writing
Headers must be set before sending any part of the response body.
Step 2: Identify the error in code order
res.write('Hello') sends body first, so setHeader after it causes error.
Final Answer:
Headers must be set before writing the response body -> Option C
Quick Check:
Set headers before body [OK]

Quick Trick: Set headers before any res.write or res.end [OK]

Common Mistakes:

Setting headers after writing body
Thinking setHeader is invalid method
Assuming res.end needs data always

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Identify the error in this Node.js code that tries to set a response header:

Step 1: Check order of header setting and response writing

Step 2: Identify the error in code order

Final Answer:

Quick Check:

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