feat: added parent/parents edges

src/core/server/graph/tenant/loaders/comments.ts

@@ -3,14 +3,35 @@ import DataLoader from "dataloader";
 import Context from "talk-server/graph/tenant/context";
 import {
   AssetToCommentsArgs,
+  CommentToParentsArgs,
   CommentToRepliesArgs,
   GQLCOMMENT_SORT,
 } from "talk-server/graph/tenant/schema/__generated__/types";
 import {
+  Comment,
   retrieveCommentAssetConnection,
+  retrieveCommentParentsConnection,
   retrieveCommentRepliesConnection,
   retrieveManyComments,
 } from "talk-server/models/comment";
+import { Connection } from "talk-server/models/connection";
+
+/**
+ * primeCommentsFromConnection will prime a given context with the comments
+ * retrieved via a connection.
+ *
+ * @param ctx graph context to use to prime the loaders.
+ */
+const primeCommentsFromConnection = (ctx: Context) => (
+  connection: Readonly<Connection<Readonly<Comment>>>
+) => {
+  // For each of the edges, prime the comment loader.
+  connection.edges.forEach(({ node }) => {
+    ctx.loaders.Comments.comment.prime(node.id, node);
+  });
+
+  return connection;
+};
 
 export default (ctx: Context) => ({
   comment: new DataLoader((ids: string[]) =>
@@ -29,7 +50,7 @@ export default (ctx: Context) => ({
       first,
       orderBy,
       after,
-    }),
+    }).then(primeCommentsFromConnection(ctx)),
   forParent: (
     assetID: string,
     parentID: string,
@@ -50,5 +71,11 @@ export default (ctx: Context) => ({
         orderBy,
         after,
       }
-    ),
+    ).then(primeCommentsFromConnection(ctx)),
+  parents: (comment: Comment, { last = 1, before }: CommentToParentsArgs) =>
+    retrieveCommentParentsConnection(ctx.mongo, ctx.tenant.id, comment, {
+      last,
+      // The cursor passed here is always going to be a number.
+      before: before as number,
+    }).then(primeCommentsFromConnection(ctx)),
 });

src/core/server/graph/tenant/resolvers/comment.ts

@@ -1,4 +1,8 @@
-import { GQLCommentTypeResolver } from "talk-server/graph/tenant/schema/__generated__/types";
+import { getRequestedFields } from "talk-server/graph/tenant/resolvers/util";
+import {
+  GQLComment,
+  GQLCommentTypeResolver,
+} from "talk-server/graph/tenant/schema/__generated__/types";
 import { Comment } from "talk-server/models/comment";
 
 const Comment: GQLCommentTypeResolver<Comment> = {
@@ -17,6 +21,30 @@ const Comment: GQLCommentTypeResolver<Comment> = {
     ctx.loaders.Users.user.load(comment.author_id),
   replies: (comment, input, ctx) =>
     ctx.loaders.Comments.forParent(comment.asset_id, comment.id, input),
+  parentCount: comment =>
+    comment.parent_id ? comment.grandparent_ids.length + 1 : 0,
+  replyCount: comment => comment.child_ids.length,
+  parent: (comment, input, ctx, info) => {
+    // If there isn't a parent, then return nothing!
+    if (!comment.parent_id) {
+      return null;
+    }
+
+    // Get the field names of the fields being requested, if it's only the ID,
+    // we have that, so no need to make a database request.
+    const fields = getRequestedFields<GQLComment>(info);
+    if (fields.length === 1 && fields[0] === "id") {
+      return {
+        id: comment.parent_id,
+      };
+    }
+
+    // We want more than the ID! Get the comment!
+    // TODO: (wyattjoh) if the parent and the parents (containing the parent) are requested, the parent comment is retrieved from the database twice. Investigate ways of reducing i/o.
+    return ctx.loaders.Comments.comment.load(comment.parent_id);
+  },
+  parents: (comment, input, ctx) =>
+    ctx.loaders.Comments.parents(comment, input),
 };
 
 export default Comment;

src/core/server/graph/tenant/resolvers/util.ts

@@ -0,0 +1,12 @@
+import { GraphQLResolveInfo } from "graphql";
+import graphqlFields from "graphql-fields";
+import { pull } from "lodash";
+
+/**
+ * getRequestedFields returns the fields in an array that are being queried for.
+ *
+ * @param info query information
+ */
+export function getRequestedFields<T>(info: GraphQLResolveInfo) {
+  return pull(Object.keys(graphqlFields<T>(info)), "__typename");
+}

src/core/server/graph/tenant/schema/schema.graphql

@@ -640,6 +640,11 @@ type Comment {
   """
   status: COMMENT_STATUS!
 
+  """
+  parentCount is the number of direct parents for this Comment.
+  """
+  parentCount: Int
+
   """
   replyCount is the number of replies. Only direct replies to this Comment
   are counted. Deleted comments are included in this count.
@@ -655,6 +660,17 @@ type Comment {
     after: Cursor
   ): CommentsConnection
 
+  """
+  parent is the immediate parent of a given comment.
+  """
+  parent: Comment
+
+  """
+  parents returns a CommentsConnection that allows accessing direct parents of
+  the given Comment.
+  """
+  parents(last: Int = 1, before: Cursor): CommentsConnection
+
   """
   editing returns details about the edit status of a Comment.
   """