# unique-operation-types

Source: https://apigenie.pl/docs/linter/graphql/rules/unique-operation-types

This rule checks that each root operation type is defined once across the schema definition and its extensions, as the GraphQL specification requires.

## Rule Details

The rule reports the issues of the validation rule of the same name, with the messages of graphql-js. A document that breaks it is rejected by GraphQL servers and tools, so the rule should stay enabled with the `error` severity.

## Configuration

This rule has no options.

```yaml
version: "1.0"
commands:
  lint:
    graphql:
      rules:
        unique-operation-types: warning
```

The rule can be disabled for a node and everything nested in it with an `# apigenie-lint-disable unique-operation-types` comment on the node, or for a whole file with the comment at the top of the file, separated from the first definition by a blank line. It applies to definitions.

## Examples

**Good**.

```graphql
schema { query: Query }
extend schema { mutation: Mutation }
```

**Bad**. The linter reports `There can be only one query type in schema.`.

```graphql
schema { query: Query }
extend schema { query: Other }
```