one-field-subscriptions

Since 0.9.0

This rule checks that subscriptions select a single root field, as the specification requires.

Rule Details

A subscription maps one event stream to responses; selecting several root fields, or an introspection field, is invalid. Inline fragments and the fragments of the document are followed.

Configuration

This rule has no options.

version: "1.0"
commands:
  lint:
    graphql:
      rules:
        one-field-subscriptions: warning

The rule can be disabled for a node and everything nested in it with an # apigenie-lint-disable one-field-subscriptions 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.

subscription OnMessage { messageAdded { id } }

Bad. The linter reports Subscription "OnEvents" must select only one top level field..

subscription OnEvents { messageAdded { id } userJoined { id } }

Further reading

• GraphQL specification