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Rule priority, scope & exceptions
Use this to align rules with the senior-level structure (P0/P1/P2, scope, exceptions/tradeoffs).
fullstack ruleP1stack specificStack: typescript
typescripttypesnull-safetyapi
Type a field as nullable when the source can return null
If an upstream can return null for a field despite its documented contract, reflect that in the type (string | null) so consumers handle it.
PR: hegnar-web · org-mining-hist-2026-06Created: Jun 19, 2026
Bad example
Old codetypescript
| 1 | interface User { |
| 2 | logoUrl: string; // but backend returns null when absent |
| 3 | } |
Explanation (EN)
A string-only declaration over nullable data permits unsafe consumers.
Objašnjenje (HR)
Good example
New codetypescript
| 1 | interface User { |
| 2 | logoUrl: string | null; |
| 3 | } |
Explanation (EN)
Objašnjenje (HR)
Notes (EN)
Describe actual external payloads, including null, then explicitly validate or map them into any stricter internal model.
Exceptions / Tradeoffs (EN)
If null violates a required business invariant, reject/repair it at the boundary rather than silently expanding the entire domain. Distinguish missing keys from null too.