void-typescript-strict

Replace any with unknown and narrow before use, typically by validating with a Zod schema whose parse method returns the typed value. A pre-commit grep hook can block new : any and as any occurrences outside fixture and test whitelists.

satisfies checks a value against a constraint while preserving its literal type, so the compiler still catches missing fields. The as cast tells the compiler to trust you and silently accepts wrong structures, which is why it is rejected outside narrow exceptions.

Prefer as const objects with a derived union type over the enum keyword, since numeric enums are loose and have surprising runtime emit. For state with multiple variants, use discriminated unions so invalid states become unrepresentable and the compiler narrows automatically.

Branded types attach a phantom tag to a primitive, so a UserId and an OrgId are both strings but not interchangeable at compile time. Create them through smart constructors that validate the raw value before returning the branded type.

With exactOptionalPropertyTypes, an optional property may be absent but cannot hold an explicit undefined, so spreading an object containing undefined values fails. Build the object literal explicitly, omitting properties instead of assigning undefined.

Use a Result<T, E> discriminated union for expected failure modes like validation errors, so the signature tells callers exactly what can go wrong. Reserve exceptions for truly unexpected bugs that callers cannot reasonably handle.