[Solved] Find the bug in this Null Object usage:class NullNotifier { notify(message) { console.... Find the bug in this Null Object usage:class NullNotifier { notify(message) { console.log(message); | LLD

LLD - Behavioral Design Patterns — Part 2

Find the bug in this Null Object usage:

class NullNotifier {
  notify(message) { console.log(message); }
}
function sendNotification(notifier, msg) {
  if (notifier != null) {
    notifier.notify(msg);
  }
}
sendNotification(null, 'Hello');

AsendNotification should not call notify at all.

Bnotify method should throw error on null message.

CThe if condition should check for undefined only.

DsendNotification should use a NullNotifier instance instead of null.

Step-by-Step Solution

Solution:

Step 1: Analyze sendNotification call
It passes null, so the if condition skips notify call.
Step 2: Correct Null Object usage
Instead of null, a NullNotifier instance should be passed to avoid null checks.
Final Answer:
sendNotification should use a NullNotifier instance instead of null. -> Option D
Quick Check:
Null Object replaces null to avoid checks [OK]

Quick Trick: Pass Null Object instance, not null [OK]

Common Mistakes:

MISTAKES

Passing null instead of Null Object
Expecting notify to handle null message
Incorrect null checks in code

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More LLD Quizzes

Find the bug in this Null Object usage:

Step 1: Analyze sendNotification call

Step 2: Correct Null Object usage

Final Answer:

Quick Check:

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