use URLSearchParams native node function

Author: HEYGUL

modules/swagger-codegen/src/main/resources/Javascript/ApiClient.mustache

@@ -2,18 +2,18 @@
 (function(root, factory) {
   if (typeof define === 'function' && define.amd) {
     // AMD. Register as an anonymous module.
-    define(['superagent', 'querystring'], factory);
+    define(['superagent'], factory);
   } else if (typeof module === 'object' && module.exports) {
     // CommonJS-like environments that support module.exports, like Node.
-    module.exports = factory(require('superagent'), require('querystring'));
+    module.exports = factory(require('superagent'));
   } else {
     // Browser globals (root is window)
     if (!root.{{moduleName}}) {
       root.{{moduleName}} = {};
     }
-    root.{{moduleName}}.ApiClient = factory(root.superagent, root.querystring);
+    root.{{moduleName}}.ApiClient = factory(root.superagent);
   }
-}(this, function(superagent, querystring) {
+}(this, function(superagent) {
   'use strict';
 
 {{#emitJSDoc}}  /**
@@ -432,7 +432,8 @@
     }
 
     if (contentType === 'application/x-www-form-urlencoded') {
-      request.send(querystring.stringify(this.normalizeParams(formParams)));
+        const searchParams = new URLSearchParams(this.normalizeParams(formParams));
+        request.send(searchParams.toString());
     } else if (contentType == 'multipart/form-data') {
       var _formParams = this.normalizeParams(formParams);
       for (var key in _formParams) {

modules/swagger-codegen/src/main/resources/Javascript/es6/ApiClient.mustache

@@ -1,6 +1,5 @@
 {{>licenseInfo}}
 import superagent from "superagent";
-import querystring from "querystring";
 
 {{#emitJSDoc}}/**
 * @module {{#invokerPackage}}{{invokerPackage}}/{{/invokerPackage}}ApiClient
@@ -420,7 +419,8 @@ export class ApiClient {
         }
 
         if (contentType === 'application/x-www-form-urlencoded') {
-            request.send(querystring.stringify(this.normalizeParams(formParams)));
+            const searchParams = new URLSearchParams(this.normalizeParams(formParams));
+            request.send(searchParams.toString());
         } else if (contentType == 'multipart/form-data') {
             var _formParams = this.normalizeParams(formParams);
             for (var key in _formParams) {

modules/swagger-codegen/src/main/resources/Javascript/package.mustache

@@ -11,8 +11,7 @@
     "fs": false
   },
   "dependencies": {
-    "superagent": "3.7.0",
-    "querystring": "0.2.0"
+    "superagent": "3.7.0"
   },
   "devDependencies": {
     "mocha": "~2.3.4",