# Refinement

`import { Refinement } from "destack:schema";`

Runtime schema refinement.

```ds title="Refinement"
export newtype interface Refinement<T> {
    issues(value: T): [Issue];
}
```

[language/library/src/schema/constraint.ds:25:28](https://github.com/destack-sh/destack/blob/main/language/library/src/schema/constraint.ds#L25-L28)

## Members

### `issues(value: T): [Issue]`

Return validation issues for `value`.