Design Patterns · Middle · Question 56 of 75

What does the Specification pattern give you for complex filters?

const isEligible = and(isActive, or(isPremium, hasOrdersOver(3)));

✓Correct answer: Small, named predicates that can be combined (and/or/not) and reused for filtering or validation
2A database schema
3A formal API specification document

Explanation

Business rules become readable building blocks instead of one long condition copied in several places.

Further reading

Fowler & Evans: Specifications ↗

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