diff --git a/src/v1beta/game_server_clusters_service_client.ts b/src/v1beta/game_server_clusters_service_client.ts
index b21a329..b008cac 100644
--- a/src/v1beta/game_server_clusters_service_client.ts
+++ b/src/v1beta/game_server_clusters_service_client.ts
@@ -107,10 +107,9 @@ export class GameServerClustersServiceClient {
       opts?.servicePath || opts?.apiEndpoint || staticMembers.servicePath;
     const port = opts?.port || staticMembers.port;
     const clientConfig = opts?.clientConfig ?? {};
-    // eslint-disable-next-line no-undef
     const fallback =
       opts?.fallback ??
-      (typeof window !== 'undefined' && typeof window.fetch !== 'undefined');
+      (typeof window !== 'undefined' && typeof window?.fetch === 'function');
     opts = Object.assign({servicePath, port, clientConfig, fallback}, opts);
 
     // If scopes are unset in options and we're connecting to a non-default endpoint, set scopes just in case.
diff --git a/src/v1beta/game_server_configs_service_client.ts b/src/v1beta/game_server_configs_service_client.ts
index daaad4f..4ef08a7 100644
--- a/src/v1beta/game_server_configs_service_client.ts
+++ b/src/v1beta/game_server_configs_service_client.ts
@@ -106,10 +106,9 @@ export class GameServerConfigsServiceClient {
       opts?.servicePath || opts?.apiEndpoint || staticMembers.servicePath;
     const port = opts?.port || staticMembers.port;
     const clientConfig = opts?.clientConfig ?? {};
-    // eslint-disable-next-line no-undef
     const fallback =
       opts?.fallback ??
-      (typeof window !== 'undefined' && typeof window.fetch !== 'undefined');
+      (typeof window !== 'undefined' && typeof window?.fetch === 'function');
     opts = Object.assign({servicePath, port, clientConfig, fallback}, opts);
 
     // If scopes are unset in options and we're connecting to a non-default endpoint, set scopes just in case.
diff --git a/src/v1beta/game_server_deployments_service_client.ts b/src/v1beta/game_server_deployments_service_client.ts
index 729338e..5f98d7d 100644
--- a/src/v1beta/game_server_deployments_service_client.ts
+++ b/src/v1beta/game_server_deployments_service_client.ts
@@ -107,10 +107,9 @@ export class GameServerDeploymentsServiceClient {
       opts?.servicePath || opts?.apiEndpoint || staticMembers.servicePath;
     const port = opts?.port || staticMembers.port;
     const clientConfig = opts?.clientConfig ?? {};
-    // eslint-disable-next-line no-undef
     const fallback =
       opts?.fallback ??
-      (typeof window !== 'undefined' && typeof window.fetch !== 'undefined');
+      (typeof window !== 'undefined' && typeof window?.fetch === 'function');
     opts = Object.assign({servicePath, port, clientConfig, fallback}, opts);
 
     // If scopes are unset in options and we're connecting to a non-default endpoint, set scopes just in case.
diff --git a/src/v1beta/realms_service_client.ts b/src/v1beta/realms_service_client.ts
index 1e672e4..37ee480 100644
--- a/src/v1beta/realms_service_client.ts
+++ b/src/v1beta/realms_service_client.ts
@@ -106,10 +106,9 @@ export class RealmsServiceClient {
       opts?.servicePath || opts?.apiEndpoint || staticMembers.servicePath;
     const port = opts?.port || staticMembers.port;
     const clientConfig = opts?.clientConfig ?? {};
-    // eslint-disable-next-line no-undef
     const fallback =
       opts?.fallback ??
-      (typeof window !== 'undefined' && typeof window.fetch !== 'undefined');
+      (typeof window !== 'undefined' && typeof window?.fetch === 'function');
     opts = Object.assign({servicePath, port, clientConfig, fallback}, opts);
 
     // If scopes are unset in options and we're connecting to a non-default endpoint, set scopes just in case.