[Solved] Examine this IPC code snippet:const { fork } = require('child_process'); const child = fork('child.js');... // child.js content: // process.send('Pong');Why does the parent never log any message? | Node.js

Node.js - Child Processes

Examine this IPC code snippet:

const { fork } = require('child_process');
const child = fork('child.js');
child.on('message', msg => console.log('Parent received:', msg));
child.send('Ping');

// child.js content:
// process.send('Pong');

Why does the parent never log any message?

ABecause 'process.send' is not a valid method in child processes

BBecause the parent sends a message before setting up the 'message' event listener

CBecause the child process never listens for messages and thus never responds to 'Ping'

DBecause the parent should use 'child.on('data')' instead of 'child.on('message')'

Step-by-Step Solution

Solution:

Step 1: Analyze child process code
The child process calls process.send('Pong') immediately but does not listen for any messages.
Step 2: Parent sends 'Ping' message
The parent sends 'Ping' to the child, but the child does not handle incoming messages, so no response is triggered.
Step 3: Why no message received?
The child sends 'Pong' only once at startup, but if the child process exits or the message is sent before IPC channel is ready, parent may not receive it.
Final Answer:
Because the child process never listens for messages and thus never responds to 'Ping' -> Option C
Quick Check:
Child must handle messages to respond [OK]

Quick Trick: Child must listen for messages to respond properly [OK]

Common Mistakes:

Assuming child automatically responds without message handler
Confusing 'message' and 'data' events
Believing process.send is invalid in child processes

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More Node.js Quizzes

Examine this IPC code snippet:

Step 1: Analyze child process code

Step 2: Parent sends 'Ping' message

Step 3: Why no message received?

Final Answer:

Quick Check:

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