diff --git a/lib/nodejs/test/client.js b/lib/nodejs/test/client.js
index 55839f6..49e3a5e 100644
--- a/lib/nodejs/test/client.js
+++ b/lib/nodejs/test/client.js
@@ -19,125 +19,149 @@
  * under the License.
  */
 
-var fs = require('fs');
-var assert = require('assert');
-var thrift = require('thrift');
-var helpers = require('./helpers');
-var ThriftTest = require('./gen-nodejs/ThriftTest');
-var ThriftTestDriver = require('./test_driver').ThriftTestDriver;
-var ThriftTestDriverPromise = require('./test_driver').ThriftTestDriverPromise;
-var SecondService = require('./gen-nodejs/SecondService');
-var ttypes = require('./gen-nodejs/ThriftTest_types');
+const assert = require("assert");
+const thrift = require("thrift");
+const helpers = require("./helpers");
 
-var program = require('commander');
+const ThriftTest = require(`./${helpers.genPath}/ThriftTest`);
+const ThriftTestDriver = require("./test_driver").ThriftTestDriver;
+const ThriftTestDriverPromise = require("./test_driver")
+  .ThriftTestDriverPromise;
+const SecondService = require(`./${helpers.genPath}/SecondService`);
+
+const program = require("commander");
 
 program
-  .option('-p, --protocol <protocol>', 'Set thrift protocol (binary|compact|json) [protocol]')
-  .option('-t, --transport <transport>', 'Set thrift transport (buffered|framed|http) [transport]')
-  .option('--port <port>', 'Set thrift server port number to connect', 9090)
-  .option('--host <host>', 'Set thrift server host to connect', 'localhost')
-  .option('--domain-socket <path>', 'Set thrift server unix domain socket to connect')
-  .option('--ssl', 'use SSL transport')
-  .option('--promise', 'test with promise style functions')
-  .option('-t, --type <type>', 'Select server type (http|multiplex|tcp|websocket)', 'tcp')
+  .option(
+    "-p, --protocol <protocol>",
+    "Set thrift protocol (binary|compact|json) [protocol]"
+  )
+  .option(
+    "-t, --transport <transport>",
+    "Set thrift transport (buffered|framed|http) [transport]"
+  )
+  .option("--port <port>", "Set thrift server port number to connect", 9090)
+  .option("--host <host>", "Set thrift server host to connect", "localhost")
+  .option(
+    "--domain-socket <path>",
+    "Set thrift server unix domain socket to connect"
+  )
+  .option("--ssl", "use SSL transport")
+  .option("--callback", "test with callback style functions")
+  .option(
+    "-t, --type <type>",
+    "Select server type (http|multiplex|tcp|websocket)",
+    "tcp"
+  )
+  .option("--es6", "Use es6 code")
+  .option("--es5", "Use es5 code")
   .parse(process.argv);
 
-var host = program.host;
-var port = program.port;
-var domainSocket = program.domainSocket;
-var type = program.type;
-var ssl = program.ssl;
-var promise = program.promise;
+const host = program.host;
+const port = program.port;
+const domainSocket = program.domainSocket;
+const ssl = program.ssl;
+let type = program.type;
 
 /* for compatibility with cross test invocation for http transport testing */
-if (program.transport === 'http') {
-  program.transport = 'buffered';
-  type = 'http';
+if (program.transport === "http") {
+  program.transport = "buffered";
+  type = "http";
 }
 
-var options = {
+const options = {
   transport: helpers.transports[program.transport],
   protocol: helpers.protocols[program.protocol]
 };
 
-if (type === 'http' || type === 'websocket') {
-  options.path = '/test';
+if (type === "http" || type === "websocket") {
+  options.path = "/test";
 }
 
-if (type === 'http') {
-  options.headers = {"Connection": "close"};
+if (type === "http") {
+  options.headers = { Connection: "close" };
 }
 
 if (ssl) {
-  if (type === 'tcp' || type === 'multiplex') {
+  if (type === "tcp" || type === "multiplex") {
     options.rejectUnauthorized = false;
-  } else if (type === 'http') {
+  } else if (type === "http") {
     options.nodeOptions = { rejectUnauthorized: false };
     options.https = true;
-  } else if (type === 'websocket') {
+  } else if (type === "websocket") {
     options.wsOptions = { rejectUnauthorized: false };
     options.secure = true;
   }
 }
 
-var connection;
-var client;
-var testDriver = promise ? ThriftTestDriverPromise : ThriftTestDriver;
+let connection;
+let client;
+const testDriver = program.callback
+  ? ThriftTestDriver
+  : ThriftTestDriverPromise;
+if (helpers.ecmaMode === "es6" && program.callback) {
+  console.log("ES6 does not support callback style");
+  process.exit(0);
+}
 
-if (type === 'tcp' || type === 'multiplex') {
+if (type === "tcp" || type === "multiplex") {
   if (domainSocket) {
     connection = thrift.createUDSConnection(domainSocket, options);
   } else {
-    connection = ssl ?
-      thrift.createSSLConnection(host, port, options) :
-      thrift.createConnection(host, port, options);
+    connection = ssl
+      ? thrift.createSSLConnection(host, port, options)
+      : thrift.createConnection(host, port, options);
   }
-} else if (type === 'http') {
+} else if (type === "http") {
   if (domainSocket) {
     connection = thrift.createHttpUDSConnection(domainSocket, options);
   } else {
     connection = thrift.createHttpConnection(host, port, options);
   }
-} else if (type === 'websocket') {
+} else if (type === "websocket") {
   connection = thrift.createWSConnection(host, port, options);
   connection.open();
 }
 
-connection.on('error', function(err) {
-    assert(false, err);
+connection.on("error", function(err) {
+  assert(false, err);
 });
 
-if (type === 'tcp') {
+if (type === "tcp") {
   client = thrift.createClient(ThriftTest, connection);
   runTests();
-} else if (type === 'multiplex') {
-  var mp = new thrift.Multiplexer();
+} else if (type === "multiplex") {
+  const mp = new thrift.Multiplexer();
   client = mp.createClient("ThriftTest", ThriftTest, connection);
-  secondclient = mp.createClient("SecondService", SecondService, connection);
+  const secondclient = mp.createClient(
+    "SecondService",
+    SecondService,
+    connection
+  );
 
-  connection.on('connect', function() {
+  connection.on("connect", function() {
     secondclient.secondtestString("Test", function(err, response) {
       assert(!err);
-      assert.equal("testString(\"Test\")", response);
+      assert.equal('testString("Test")', response);
     });
 
     runTests();
   });
-} else if (type === 'http') {
+} else if (type === "http") {
   client = thrift.createHttpClient(ThriftTest, connection);
   runTests();
-} else if (type === 'websocket') {
+} else if (type === "websocket") {
   client = thrift.createWSClient(ThriftTest, connection);
   runTests();
 }
 
 function runTests() {
-  testDriver(client, function (status) {
+  testDriver(client, function(status) {
     console.log(status);
-    if (type !== 'http' && type !== 'websocket') {
+    if (type !== "http" && type !== "websocket") {
       connection.end();
     }
-    if (type !== 'multiplex') {
+    if (type !== "multiplex") {
       process.exit(0);
     }
   });