Merge pull request #3341 from rmosolgo/range-add-improvements

Improve RangeAdd and add a guide

guides/relay/range_add.md

@@ -0,0 +1,11 @@
+---
+layout: guide
+doc_stub: false
+search: true
+section: Relay
+title: RangeAdd helper for mutations
+desc: A helper for Relay's RANGE_ADD operations
+index: 1
+---
+
+Relay specifies `RANGE_ADD` operations for adding items to connections. GraphQL-Ruby ships with {{ "GraphQL::Relay::RangeAdd" | api_doc }} to help implement this. Check the API docs for a usage example.

guides/schema/sdl.md

@@ -78,7 +78,7 @@ The hash may contain:
 
 ## Plugins
 
-{ "GraphQL::Schema.from_definition" | api_doc }} accepts a `using:` argument, which may be given as a map of `plugin => args` pairs. For example:
+{{ "GraphQL::Schema.from_definition" | api_doc }} accepts a `using:` argument, which may be given as a map of `plugin => args` pairs. For example:
 
 ```ruby
 MySchema = GraphQL::Schema.from_definition("path/to/schema.graphql", using: {

lib/graphql/pagination/connection.rb

@@ -105,6 +105,15 @@ def first
         end
       end
 
+      # This is called by `Relay::RangeAdd` -- it can be overridden
+      # when `item` needs some modifications based on this connection's state.
+      #
+      # @param item [Object] An item newly added to `items`
+      # @return [Edge]
+      def range_add_edge(item)
+        edge_class.new(item, self)
+      end
+
       attr_writer :last
       # @return [Integer, nil] A clamped `last` value. (The underlying instance variable doesn't have limits on it)
       def last

lib/graphql/relay/range_add.rb

@@ -9,7 +9,7 @@ module Relay
     # should be ordered and paginated before providing it here.
     #
     # @example Adding a comment to list of comments
-    #   post = Post.find(args[:postId])
+    #   post = Post.find(args[:post_id])
     #   comments = post.comments
     #   new_comment = comments.build(body: args[:body])
     #   new_comment.save!
@@ -18,13 +18,13 @@ module Relay
     #     parent: post,
     #     collection: comments,
     #     item: new_comment,
-    #     context: ctx,
+    #     context: context,
     #   )
     #
     #   response = {
     #     post: post,
-    #     commentsConnection: range_add.connection,
-    #     newCommentEdge: range_add.edge,
+    #     comments_connection: range_add.connection,
+    #     new_comment_edge: range_add.edge,
     #   }
     class RangeAdd
       attr_reader :edge, :connection, :parent
@@ -39,7 +39,12 @@ def initialize(collection:, item:, parent: nil, context: nil, edge_class: nil)
           conn_class = context.schema.connections.wrapper_for(collection)
           # The rest will be added by ConnectionExtension
           @connection = conn_class.new(collection, parent: parent, context: context, edge_class: edge_class)
-          @edge = @connection.edge_class.new(item, @connection)
+          # Check if this connection supports it, to support old versions of GraphQL-Pro
+          @edge = if @connection.respond_to?(:range_add_edge)
+            @connection.range_add_edge(item)
+          else
+            @connection.edge_class.new(item, @connection)
+          end
         else
           connection_class = BaseConnection.connection_for_nodes(collection)
           @connection = connection_class.new(collection, {}, parent: parent, context: context)