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

Published by Jason Bahl

Jason is a Principal Software Engineer at WP Engine based in Denver, CO where he maintains WPGraphQL. When he's not writing code or evangelizing about GraphQL to the world, he enjoys escaping from escape rooms, playing soccer, board games and Fortnite.