diff --git a/src/commit.ts b/src/commit.ts
index 0c79a747..ff6f5a6e 100644
--- a/src/commit.ts
+++ b/src/commit.ts
@@ -57,8 +57,7 @@ export class Commit {
       this.parent ? [...this.parent] : []);
     commit.hash = this.hash;
 
-    commit.tags = [];
-    if (this.tags != null) {
+    if (this.tags.length > 0) {
       commit.tags = [...this.tags];
     }
 
@@ -85,10 +84,6 @@ export class Commit {
       return;
     }
 
-    if (this.tags == null) {
-      this.tags = [];
-    }
-
     if (this.tags.includes(tag)) {
       return;
     }
diff --git a/src/odb.ts b/src/odb.ts
index 40774031..24f819d3 100644
--- a/src/odb.ts
+++ b/src/odb.ts
@@ -135,6 +135,14 @@ export class Odb {
         return commits.map((commit: any) => {
           const tmpCommit = commit;
 
+          if (!tmpCommit.tags) {
+            tmpCommit.tags = [];
+          }
+
+          if (!tmpCommit.userData) {
+            tmpCommit.userData = {};
+          }
+
           tmpCommit.date = new Date(tmpCommit.date); // convert number from JSON into date object
           const c: Commit = Object.setPrototypeOf(tmpCommit, Commit.prototype);
           c.repo = this.repo;
diff --git a/src/reference.ts b/src/reference.ts
index 92f96a39..4cf87979 100644
--- a/src/reference.ts
+++ b/src/reference.ts
@@ -63,7 +63,7 @@ export class Reference {
         });
 
       ref.userData = {};
-      if (this.userData != null) {
+      if (this.userData !== null) {
         ref.userData = { ...this.userData };
       }