# Decorators

- JS/TS already sorta kinda has decorators, sometimes
- extended placement
- decorators on expressions
- newtypes as decorators
- incl. union newtypes

- queryable
- [`@if` static gating](/docs/language/typescript/static-ifs/)

- `@allow`, `@warn`, `@deny`, `@forbid`, and `@expect` tune diagnostics lexically; conditional forms may use static metadata and carry a reason
- `@unsafe` marks an unsafe operation, while `@safe` exposes a checked API whose implementation contains unsafe operations
- `@derive` synthesizes compiler-known interfaces such as `Copy`, `SharedSafe`, `Clone`, `Default`, comparison, formatting, hashing, and serialization capabilities