WPGraphQL

Tag: Schema Customization

  • Deprecating a field in the Schema

    Sometimes it can be helpful to deprecate a field in the Schema without removing it altogether.

    This snippet shows how to deprecate the `Post.excerpt` field.

    You can use this technique to deprecate other fields. 

    // Filter the Object Fields
add_filter( 'graphql_object_fields', function( $fields, $type_name, $wp_object_type, $type_registry ) {

        // If the Object Type is not the "Post" Type
        // return the fields unaltered
	if ( 'Post' !== $type_name ) {
		return $fields;
	}

        // If the excerpt field doesn't exist 
        // (removed by another plugin, for example)
        // return the fields unaltered
	if ( ! isset( $fields['excerpt'] ) ) {
		return  $fields;
	}

        // Add a deprecation reason to the excerpt field
	$fields['excerpt']['deprecationReason'] = __( 'Just showing how to deprecate an existing field', 'your-textdomain' );
	
        // return the modified
        return $fields;

}, 10, 4 );

    After using this snippet, we can verify in the WPGraphQL Schema Docs that the field is indeed deprecated:

    Screenshot of the excerpt field showing deprecated in the GraphiQL IDE Schema Docs

  • Register a basic Mutation

    This snippet shows how to register a basic GraphQL Mutation with a single input field, a single output field, and the input is simply returned as the value for the output. 

    add_action( 'graphql_register_types', function() {

	register_graphql_mutation( 'testMutation', [
		'inputFields' => [
			'phoneNumber' => [
				'type' => [ 'non_null' => 'String' ],
			],
		],
		'outputFields' => [
			'phoneNumber' => [
				'type' => 'String',
			],
		],
		'mutateAndGetPayload' => function( $input ) {

			return [
				'phoneNumber' => $input['phoneNumber'] ?? null,
			];

		}
	]);

} );