[Solved] Which of the following is a correct way to define a Null Object class in a system design context? - Ans: class NullLogger { log(message) { /* do nothing */ } } | LLD

LLD - Behavioral Design Patterns — Part 2

Which of the following is a correct way to define a Null Object class in a system design context?

Aclass NullLogger { log(message) { throw new Error('Null'); } }

Bclass NullLogger { log(message) { console.error(message); } }

Cclass NullLogger { log(message) { return null; } }

Dclass NullLogger { log(message) { /* do nothing */ } }

Step-by-Step Solution

Solution:

Step 1: Understand Null Object behavior
It should implement the interface with safe, do-nothing methods.
Step 2: Evaluate options
class NullLogger { log(message) { /* do nothing */ } } does nothing safely. class NullLogger { log(message) { throw new Error('Null'); } } throws error, C returns null (not safe), D logs error (not silent).
Final Answer:
class NullLogger { log(message) { /* do nothing */ } } -> Option D
Quick Check:
Null Object method = safe no-op [OK]

Quick Trick: Null Object methods do nothing safely [OK]

Common Mistakes:

MISTAKES

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Which of the following is a correct way to define a Null Object class in a system design context?