1 files changed, 52 insertions, 0 deletions
diff --git a/app/graphql/resolvers/concerns/looks_ahead.rb b/app/graphql/resolvers/concerns/looks_ahead.rb
new file mode 100644
index 00000000000..becc6debd33
--- /dev/null
+++ b/app/graphql/resolvers/concerns/looks_ahead.rb
@@ -0,0 +1,52 @@
+# frozen_string_literal: true
+
+module LooksAhead
+  extend ActiveSupport::Concern
+
+  FEATURE_FLAG = :graphql_lookahead_support
+
+  included do
+    attr_accessor :lookahead
+  end
+
+  def resolve(**args)
+    self.lookahead = args.delete(:lookahead)
+
+    resolve_with_lookahead(**args)
+  end
+
+  def apply_lookahead(query)
+    return query unless Feature.enabled?(FEATURE_FLAG)
+
+    selection = node_selection
+
+    includes = preloads.each.flat_map do |name, requirements|
+      selection&.selects?(name) ? requirements : []
+    end
+    preloads = (unconditional_includes + includes).uniq
+
+    return query if preloads.empty?
+
+    query.preload(*preloads) # rubocop: disable CodeReuse/ActiveRecord
+  end
+
+  private
+
+  def unconditional_includes
+    []
+  end
+
+  def preloads
+    {}
+  end
+
+  def node_selection
+    return unless lookahead
+
+    if lookahead.selects?(:nodes)
+      lookahead.selection(:nodes)
+    elsif lookahead.selects?(:edges)
+      lookahead.selection(:edges).selection(:nodes)
+    end
+  end
+end