1 files changed, 30 insertions, 0 deletions
diff --git a/src/services/graphql/helpers/build-comments-tree.ts b/src/services/graphql/helpers/build-comments-tree.ts
new file mode 100644
index 0000000..1534cfe
--- /dev/null
+++ b/src/services/graphql/helpers/build-comments-tree.ts
@@ -0,0 +1,30 @@
+import type { SingleComment } from '../../../types';
+
+/**
+ * Create a comments tree with replies.
+ *
+ * @param {SingleComment[]} comments - A flatten comments list.
+ * @returns {SingleComment[]} An array of comments with replies.
+ */
+export const buildCommentsTree = (
+  comments: SingleComment[]
+): SingleComment[] => {
+  type CommentsHashTable = Record<string, SingleComment>;
+
+  const hashTable: CommentsHashTable = Object.create(null);
+  const commentsTree: SingleComment[] = [];
+
+  comments.forEach((comment) => {
+    hashTable[comment.id] = { ...comment, replies: [] };
+  });
+
+  comments.forEach((comment) => {
+    if (comment.parentId) {
+      hashTable[comment.parentId].replies.push(hashTable[comment.id]);
+    } else {
+      commentsTree.push(hashTable[comment.id]);
+    }
+  });
+
+  return commentsTree;
+};