refactor: small refactoring for readability

@KapilJ your solution is right now the best solution, I think. Probably
the ideal solution would be if we could implement the `CreateComment`
resolver in such a way that it is doing eager loading of the
`comment->post->author` relationship and resolving a commment object
which has the required objects all set. Then you wouldn't have to
refetch all the stuff.

But I think this is OK for now 👍

backend/src/middleware/notifications/notificationsMiddleware.js

@@ -1,5 +1,21 @@
 import extractMentionedUsers from './mentions/extractMentionedUsers'
 
+const postAuthorOfComment = async (comment, { context }) => {
+  const session = context.driver.session()
+  const cypherFindUser = `
+    MATCH (user: User)-[:WROTE]->(:Post)<-[:COMMENTS]-(:Comment { id: $commentId })
+    RETURN user { .id }
+    `
+  const result = await session.run(cypherFindUser, {
+    commentId: comment.id,
+  })
+  session.close()
+  const [postAuthor] = await result.records.map(record => {
+    return record.get('user')
+  })
+  return postAuthor
+}
+
 const notifyUsers = async (label, id, idsOfUsers, reason, context) => {
   if (!idsOfUsers.length) return
 
@@ -90,27 +106,12 @@ const handleContentDataOfPost = async (resolve, root, args, context, resolveInfo
 }
 
 const handleContentDataOfComment = async (resolve, root, args, context, resolveInfo) => {
-  const idsOfUsers = extractMentionedUsers(args.content)
+  let idsOfUsers = extractMentionedUsers(args.content)
   const comment = await resolve(root, args, context, resolveInfo)
 
   if (comment) {
-    const session = context.driver.session()
-    const cypherFindUser = `
-    MATCH (user: User)-[:WROTE]->(:Post)<-[:COMMENTS]-(:Comment { id: $commentId })
-    RETURN user { .id }
-    `
-    const result = await session.run(cypherFindUser, {
-      commentId: comment.id,
-    })
-    session.close()
-    const [postAuthor] = await result.records.map(record => {
-      return record.get('user')
-    })
-    var index = idsOfUsers.indexOf(postAuthor.id)
-
-    if (index > -1) {
-      idsOfUsers.splice(index)
-    }
+    const postAuthor = await postAuthorOfComment(comment, { context })
+    idsOfUsers = idsOfUsers.filter(id => id !== postAuthor.id)
 
     await notifyUsers('Comment', comment.id, idsOfUsers, 'mentioned_in_comment', context)
   }

backend/src/middleware/notifications/notificationsMiddleware.spec.js

@@ -479,7 +479,7 @@ describe('notifications', () => {
           })
 
           beforeEach(async () => {
-            title = 'Post where Im the author and I get mentioned in a comment'
+            title = "Post where I'm the author and I get mentioned in a comment"
             postContent = 'Content of post where I get mentioned in a comment.'
             postAuthor = notifiedUser
           })