Computed vs watch for a filterable Vue catalog

Learning goals

• Is this derived state or a real side effect?
• Will this create duplicate state?
• Do you need explicit timing and cleanup?
• Which choice keeps the component easiest to read?

Key decisions to discuss

• Pick a direction for this exact prompt, not the universal winner.
• State the trade-off that matters most for this scenario.
• Name when another option becomes the better answer.
• Keep the explanation grounded in concrete constraints.

Evaluation rubric

• Strong answers tie the recommendation to the prompt.
• Good tradeoff reasoning explains downsides, not just upsides.
• The answer should show when the recommendation stops being right.
• Follow-up pressure should not break the argument.

Constraints / Requirements

• Which direction would you defend for this prompt, and how would you explain when the other option becomes…
• Usually the stronger answer when the UI state is purely derived from other reactive inputs and…
• The better answer when the job is to react to state changes by causing effects, not…

Options on the table

Computed-first approach: Usually the stronger answer when the UI state is purely derived from other reactive…
Watch-based syncing: The better answer when the job is to react to state changes by causing…

Common pitfalls

• Arguing from preference instead of prompt constraints.
• Pretending one option is always the winner.
• Ignoring the main downside of the chosen direction.
• Failing to explain when the alternative becomes stronger.

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