[API reference](https://evolu.dev/docs/api-reference) › [@evolu/common](https://evolu.dev/docs/api-reference/common) › [Type](https://evolu.dev/docs/api-reference/common/Type) › MapIssue

```ts
type MapIssue<KeyError, ValueError, StructuralIssue> =
  MapKeyIssue<KeyError> | MapValueIssue<ValueError> | StructuralIssue;
```

Defined in: [packages/common/src/Type.ts:8668](https://github.com/evoluhq/evolu/blob/037c390af081e9944d616ff298a729515c5c5ab7/packages/common/src/Type.ts#L8668)

An invalid key, value, or structure in a [map](https://evolu.dev/docs/api-reference/common/Type/functions/map).