# no-undefined-variables

Source: https://apigenie.pl/docs/linter/graphql/rules/no-undefined-variables

This rule checks that the variables used by an operation, including in the fragments it spreads, are defined by the operation, 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:
        no-undefined-variables: warning
```

The rule can be disabled for a node and everything nested in it with an `# apigenie-lint-disable no-undefined-variables` 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 operations and fragments.

## Examples

**Good**.

```graphql
query Q($id: ID!) { user(id: $id) { id } }
```

**Bad**. The linter reports `Variable "$id" is not defined by operation "Q".`.

```graphql
query Q { user(id: $id) { id } }
```