class GraphQL::StaticValidation::OperationNamesAreValid

def validate(context)
  op_names = Hash.new { |h, k| h[k] = [] }
  context.visitor[GraphQL::Language::Nodes::OperationDefinition].enter << ->(node, _parent) {
    op_names[node.name] << node
  }
  context.visitor[GraphQL::Language::Nodes::Document].leave << ->(node, _parent) {
    op_count = op_names.values.inject(0) { |m, v| m + v.size }
    op_names.each do |name, nodes|
      if name.nil? && op_count > 1
        context.errors << message(%|Operation name is required when multiple operations are present|, nodes, context: context)
      elsif nodes.length > 1
        context.errors << message(%|Operation name "#{name}" must be unique|, nodes, context: context)
      end
    end
  }
end