diff --git a/__tests__/utils/fetch.js b/__tests__/utils/fetch.js
new file mode 100644
index 0000000..b55a89c
--- /dev/null
+++ b/__tests__/utils/fetch.js
@@ -0,0 +1,25 @@
+import * as fetch from '../../src/utils/fetch';
+
+describe('utils.fetch#encodeQueryData', () => {
+  test('should create valid query string', () => {
+    const result1 = fetch.encodeQueryData({
+      a: 1,
+      b: true,
+      c: null,
+      d: 'foo',
+      e: undefined
+    });
+
+    const result2 = fetch.encodeQueryData({
+      a: 1,
+      b: {
+        c: {
+          d: 'foo'
+        }
+      }
+    });
+
+    expect(result1).toEqual('a=1&b=true&d=foo');
+    expect(result2).toEqual('a=1&b=%7B%22c%22%3A%7B%22d%22%3A%22foo%22%7D%7D');
+  });
+});
diff --git a/src/adapters/vfs/system.js b/src/adapters/vfs/system.js
index ceee251..16dcfd9 100644
--- a/src/adapters/vfs/system.js
+++ b/src/adapters/vfs/system.js
@@ -59,7 +59,7 @@ const methods = (core, request) => {
   return {
     readdir: ({path}, options) => request('readdir', {
       path,
-      options: {}
+      options,
     }, 'json').then(({body}) => body),
 
     readfile: ({path}, type, options) =>
diff --git a/src/utils/fetch.js b/src/utils/fetch.js
index 46508e9..aaa6bfc 100644
--- a/src/utils/fetch.js
+++ b/src/utils/fetch.js
@@ -28,13 +28,20 @@
  * @license Simplified BSD License
  */
 
+
 /*
  * Creates URL request path
  */
-const encodeQueryData = data => Object.keys(data)
-  .filter(k => typeof data[k] !== 'object')
-  .map(k => encodeURIComponent(k) + '=' + encodeURIComponent(data[k]))
-  .join('&');
+export const encodeQueryData = (data) => {
+  const pairs = Object.entries(data)
+    .filter(([, val]) => val !== null && val !== undefined)
+    .map(([key, val]) => {
+      const value = typeof val === 'object' ? JSON.stringify(val) : val;
+      return `${encodeURIComponent(key)}=${encodeURIComponent(value)}`;
+    });
+
+  return pairs.join('&');
+};
 
 const bodyTypes = [
   window.ArrayBuffer,
@@ -65,7 +72,9 @@ const createFetchOptions = (url, options, type) => {
   }
 
   if (fetchOptions.body && fetchOptions.method.toLowerCase() === 'get') {
-    url += '?' + encodeQueryData(fetchOptions.body);
+    if(encodeQueryData(fetchOptions.body) !== '') {
+      url += '?' + encodeQueryData(fetchOptions.body);
+    }
     delete fetchOptions.body;
   }