[Solved] Consider the following code snippet:function readFile(callback) { setTimeout(() => { callback(null, 'file content'); }, 100);... } });What will be printed to the console? | Node.js

Node.js - Error Handling Patterns

Consider the following code snippet:

function readFile(callback) {
  setTimeout(() => {
    callback(null, 'file content');
  }, 100);
}

readFile((err, data) => {
  if (err) {
    console.log('Error:', err);
  } else {
    console.log('Data:', data);
  }
});

What will be printed to the console?

AError: null

BData: file content

CError: file content

DNothing will be printed

Step-by-Step Solution

Solution:

Step 1: Analyze the callback invocation
The callback is called with null as error and 'file content' as data after 100ms.
Step 2: Check the callback logic
Since err is null (no error), the else branch runs and logs 'Data: file content'.
Final Answer:
Data: file content -> Option B
Quick Check:
Null error means success, so data logs [OK]

Quick Trick: Null error means no error, print data [OK]

Common Mistakes:

Printing error when error is null
Confusing error and data values
Expecting no output due to async

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More Node.js Quizzes

Consider the following code snippet:

Step 1: Analyze the callback invocation

Step 2: Check the callback logic

Final Answer:

Quick Check:

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