[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) › UnionError

```ts
type UnionError<Error, MemberError> = [Error] extends [never]
  ? never
  : UnionErrorValue<Error, MemberError>;
```

Defined in: [packages/common/src/Type.ts:3892](https://github.com/evoluhq/evolu/blob/037c390af081e9944d616ff298a729515c5c5ab7/packages/common/src/Type.ts#L3892)

Error returned when every member of a [union](https://evolu.dev/docs/api-reference/common/Type/functions/union) rejects an input.