diff --git a/modules/openapi-generator/src/main/resources/Javascript/ApiClient.mustache b/modules/openapi-generator/src/main/resources/Javascript/ApiClient.mustache
index dcea1e0da57..6fb2e025160 100644
--- a/modules/openapi-generator/src/main/resources/Javascript/ApiClient.mustache
+++ b/modules/openapi-generator/src/main/resources/Javascript/ApiClient.mustache
@@ -137,6 +137,7 @@
     }
     var url = this.basePath + path;
 
+
     // use API (operation, path) base path if defined
     if (apiBasePath !== null && apiBasePath !== undefined) {
         url = apiBasePath + path;
@@ -664,7 +665,8 @@
         // go through variable and assign a value
         for (var variable_name in server['variables']) {
             if (variable_name in variables) {
-                if (server['variables'][variable_name]['enum_values'].includes(variables[variable_name])) {
+                let variable = server['variables'][variable_name];
+                if ( !('enum_values' in variable) || variable['enum_values'].includes(variables[variable_name]) ) {
                     url = url.replace("{" + variable_name + "}", variables[variable_name]);
                 } else {
                     throw new Error("The variable `" + variable_name + "` in the host URL has invalid value " + variables[variable_name] + ". Must be " + server['variables'][variable_name]['enum_values'] + ".");
diff --git a/modules/openapi-generator/src/main/resources/Javascript/es6/ApiClient.mustache b/modules/openapi-generator/src/main/resources/Javascript/es6/ApiClient.mustache
index 1bc2b93cc1a..15cc588f06b 100644
--- a/modules/openapi-generator/src/main/resources/Javascript/es6/ApiClient.mustache
+++ b/modules/openapi-generator/src/main/resources/Javascript/es6/ApiClient.mustache
@@ -645,7 +645,8 @@ class ApiClient {
         // go through variable and assign a value
         for (var variable_name in server['variables']) {
             if (variable_name in variables) {
-                if (server['variables'][variable_name]['enum_values'].includes(variables[variable_name])) {
+                let variable = server['variables'][variable_name];
+                if ( !('enum_values' in variable) || variable['enum_values'].includes(variables[variable_name]) ) {
                     url = url.replace("{" + variable_name + "}", variables[variable_name]);
                 } else {
                     throw new Error("The variable `" + variable_name + "` in the host URL has invalid value " + variables[variable_name] + ". Must be " + server['variables'][variable_name]['enum_values'] + ".");
diff --git a/samples/client/petstore/javascript-es6/src/ApiClient.js b/samples/client/petstore/javascript-es6/src/ApiClient.js
index 2f3db709d0f..d7f02559669 100644
--- a/samples/client/petstore/javascript-es6/src/ApiClient.js
+++ b/samples/client/petstore/javascript-es6/src/ApiClient.js
@@ -576,7 +576,8 @@ class ApiClient {
         // go through variable and assign a value
         for (var variable_name in server['variables']) {
             if (variable_name in variables) {
-                if (server['variables'][variable_name]['enum_values'].includes(variables[variable_name])) {
+                let variable = server['variables'][variable_name];
+                if ( !('enum_values' in variable) || variable['enum_values'].includes(variables[variable_name]) ) {
                     url = url.replace("{" + variable_name + "}", variables[variable_name]);
                 } else {
                     throw new Error("The variable `" + variable_name + "` in the host URL has invalid value " + variables[variable_name] + ". Must be " + server['variables'][variable_name]['enum_values'] + ".");
diff --git a/samples/client/petstore/javascript-promise-es6/src/ApiClient.js b/samples/client/petstore/javascript-promise-es6/src/ApiClient.js
index 1a8705972db..592ca85f397 100644
--- a/samples/client/petstore/javascript-promise-es6/src/ApiClient.js
+++ b/samples/client/petstore/javascript-promise-es6/src/ApiClient.js
@@ -575,7 +575,8 @@ class ApiClient {
         // go through variable and assign a value
         for (var variable_name in server['variables']) {
             if (variable_name in variables) {
-                if (server['variables'][variable_name]['enum_values'].includes(variables[variable_name])) {
+                let variable = server['variables'][variable_name];
+                if ( !('enum_values' in variable) || variable['enum_values'].includes(variables[variable_name]) ) {
                     url = url.replace("{" + variable_name + "}", variables[variable_name]);
                 } else {
                     throw new Error("The variable `" + variable_name + "` in the host URL has invalid value " + variables[variable_name] + ". Must be " + server['variables'][variable_name]['enum_values'] + ".");
diff --git a/samples/client/petstore/javascript-promise/src/ApiClient.js b/samples/client/petstore/javascript-promise/src/ApiClient.js
index 3416af28c95..0e979efba3f 100644
--- a/samples/client/petstore/javascript-promise/src/ApiClient.js
+++ b/samples/client/petstore/javascript-promise/src/ApiClient.js
@@ -136,6 +136,7 @@
     }
     var url = this.basePath + path;
 
+
     // use API (operation, path) base path if defined
     if (apiBasePath !== null && apiBasePath !== undefined) {
         url = apiBasePath + path;
@@ -611,7 +612,8 @@
         // go through variable and assign a value
         for (var variable_name in server['variables']) {
             if (variable_name in variables) {
-                if (server['variables'][variable_name]['enum_values'].includes(variables[variable_name])) {
+                let variable = server['variables'][variable_name];
+                if ( !('enum_values' in variable) || variable['enum_values'].includes(variables[variable_name]) ) {
                     url = url.replace("{" + variable_name + "}", variables[variable_name]);
                 } else {
                     throw new Error("The variable `" + variable_name + "` in the host URL has invalid value " + variables[variable_name] + ". Must be " + server['variables'][variable_name]['enum_values'] + ".");
diff --git a/samples/client/petstore/javascript/src/ApiClient.js b/samples/client/petstore/javascript/src/ApiClient.js
index ed27f48fde1..7aa1c8ce42f 100644
--- a/samples/client/petstore/javascript/src/ApiClient.js
+++ b/samples/client/petstore/javascript/src/ApiClient.js
@@ -136,6 +136,7 @@
     }
     var url = this.basePath + path;
 
+
     // use API (operation, path) base path if defined
     if (apiBasePath !== null && apiBasePath !== undefined) {
         url = apiBasePath + path;
@@ -622,7 +623,8 @@
         // go through variable and assign a value
         for (var variable_name in server['variables']) {
             if (variable_name in variables) {
-                if (server['variables'][variable_name]['enum_values'].includes(variables[variable_name])) {
+                let variable = server['variables'][variable_name];
+                if ( !('enum_values' in variable) || variable['enum_values'].includes(variables[variable_name]) ) {
                     url = url.replace("{" + variable_name + "}", variables[variable_name]);
                 } else {
                     throw new Error("The variable `" + variable_name + "` in the host URL has invalid value " + variables[variable_name] + ". Must be " + server['variables'][variable_name]['enum_values'] + ".");