fix: 🐛 use nil check instead of error check

users/service.go

@@ -81,12 +81,12 @@ func SaveUserToken(ctx context.Context, app *core.App, spotifyID string, token *
 
 	coll := app.MongoClient.Database("listy").Collection("users")
 
-	result, err := GetUser(ctx, app, spotifyID)
+	user, err := GetUser(ctx, app, spotifyID)
 	if err != nil && !errors.Is(err, mongo.ErrNoDocuments) {
 		return nil, fmt.Errorf("couldn't fetch user %w", err)
 	}
 
-	if err == mongo.ErrNoDocuments {
+	if user == nil {
 		doc := models.User{Token: *token, SpotifyID: spotifyID}
 		_, err = coll.InsertOne(context.TODO(), doc)
 
@@ -94,14 +94,14 @@ func SaveUserToken(ctx context.Context, app *core.App, spotifyID string, token *
 			return nil, fmt.Errorf("couldn't write user %w", err)
 		}
 	} else {
-		_, err := coll.UpdateByID(ctx, result.ID, bson.D{{"$set", bson.D{{"token", *token}}}})
+		_, err := coll.UpdateByID(ctx, user.ID, bson.D{{"$set", bson.D{{"token", *token}}}})
 
 		if err != nil {
 			return nil, fmt.Errorf("couldn't write user %w", err)
 		}
 
-		result.Token = *token
+		user.Token = *token
 	}
 
-	return result, nil
+	return user, nil
 }