diff --git a/common/js/types.d.ts b/common/js/types.d.ts
index 01a89e2c6..6f8248b13 100644
--- a/common/js/types.d.ts
+++ b/common/js/types.d.ts
@@ -378,7 +378,7 @@ interface SessionCalculatedDataLookup {
     "gitadora:Gita": "skill";
     "gitadora:Dora": "skill";
 }
-export interface SessionDocument<I extends IDStrings> extends MongoDBDocument {
+export interface SessionDocument<I extends IDStrings = IDStrings> extends MongoDBDocument {
     userID: integer;
     sessionID: string;
     scoreInfo: SessionScoreInfo[];
diff --git a/common/src/types.ts b/common/src/types.ts
index ef15ae2d0..207b73964 100644
--- a/common/src/types.ts
+++ b/common/src/types.ts
@@ -544,7 +544,7 @@ interface SessionCalculatedDataLookup {
     "gitadora:Dora": "skill";
 }
 
-export interface SessionDocument<I extends IDStrings> extends MongoDBDocument {
+export interface SessionDocument<I extends IDStrings = IDStrings> extends MongoDBDocument {
     userID: integer;
     sessionID: string;
     scoreInfo: SessionScoreInfo[];