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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
typescriptasynctypescorrectness
Type async functions as returning a Promise
An async function always returns a Promise, so its annotated return type must be Promise<T>, not T.
PR: vinify-frontend · org-mining-hist-2026-06Created: Jun 19, 2026
Bad example
Old codetypescript
| 1 | const geocode = async (place: string): CoordsWithLocationName | null => { /* ... */ }; |
Explanation (EN)
An async function resolves its return value through a promise, so a direct T annotation misstates its contract.
Objašnjenje (HR)
Good example
New codetypescript
| 1 | const geocode = async (place: string): Promise<CoordsWithLocationName | null> => { /* ... */ }; |
Explanation (EN)
Objašnjenje (HR)
Notes (EN)
For an explicitly annotated TypeScript async function, annotate Promise<T> for the resolved value domain and include null/undefined only when the implementation can resolve them.
Exceptions / Tradeoffs (EN)
An inferred return type is sufficient for local helpers when project conventions allow it.