diff --git a/CHANGELOG.md b/CHANGELOG.md
index 60e420e..596b5be 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # CHANGELOG 📝
 
+## v0.4.1 2024/04/29
+
+- Feat: remove `undefined` value in `params` / `data`
+
 ## v0.4.0 2024/04/24
 
 **Breaking Change**
diff --git a/Mock-plugin.md b/Mock-plugin.md
index bbf8c73..0747f98 100644
--- a/Mock-plugin.md
+++ b/Mock-plugin.md
@@ -61,8 +61,8 @@ instance.get('/api/hello').then((res) => {
 Using jsDelivr CDN:
 
 ```html
-<script src="https://cdn.jsdelivr.net/npm/xior@0.4.0/dist/xior.umd.js"></script>
-<script src="https://cdn.jsdelivr.net/npm/xior@0.4.0/plugins/mock.umd.js"></script>
+<script src="https://cdn.jsdelivr.net/npm/xior@0.4.1/dist/xior.umd.js"></script>
+<script src="https://cdn.jsdelivr.net/npm/xior@0.4.1/plugins/mock.umd.js"></script>
 
 <!-- Usage -->
 <script>
@@ -79,8 +79,8 @@ Using jsDelivr CDN:
 Using unpkg CDN:
 
 ```html
-<script src="https://unpkg.com/xior@0.4.0/dist/xior.umd.js"></script>
-<script src="https://unpkg.com/xior@0.4.0/plugins/mock.umd.js"></script>
+<script src="https://unpkg.com/xior@0.4.1/dist/xior.umd.js"></script>
+<script src="https://unpkg.com/xior@0.4.1/plugins/mock.umd.js"></script>
 
 <!-- Usage -->
 <script>
diff --git a/README.md b/README.md
index 00be59e..7ff232e 100644
--- a/README.md
+++ b/README.md
@@ -121,7 +121,7 @@ yarn add xior
 Use jsDelivr CDN:
 
 ```html
-<script src="https://cdn.jsdelivr.net/npm/xior@0.4.0/dist/xior.umd.js"></script>
+<script src="https://cdn.jsdelivr.net/npm/xior@0.4.1/dist/xior.umd.js"></script>
 
 <!-- Usage -->
 <script>
@@ -136,7 +136,7 @@ Use jsDelivr CDN:
 Use unpkg CDN:
 
 ```html
-<script src="https://unpkg.com/xior@0.4.0/dist/xior.umd.js"></script>
+<script src="https://unpkg.com/xior@0.4.1/dist/xior.umd.js"></script>
 
 <!-- Usage -->
 <script>
@@ -660,9 +660,9 @@ Use CDN:
 Using jsDelivr CDN:
 
 ```html
-<script src="https://cdn.jsdelivr.net/npm/xior@0.4.0/dist/xior.umd.js"></script>
+<script src="https://cdn.jsdelivr.net/npm/xior@0.4.1/dist/xior.umd.js"></script>
 <!-- Load plugin -->
-<script src="https://cdn.jsdelivr.net/npm/xior@0.4.0/plugins/error-retry.umd.js"></script>
+<script src="https://cdn.jsdelivr.net/npm/xior@0.4.1/plugins/error-retry.umd.js"></script>
 
 <!-- Usage -->
 <script>
@@ -675,10 +675,10 @@ Using jsDelivr CDN:
 Using unpkg CDN:
 
 ```html
-<script src="https://unpkg.com/xior@0.4.0/dist/xior.umd.js"></script>
+<script src="https://unpkg.com/xior@0.4.1/dist/xior.umd.js"></script>
 
 <!-- Load plugin -->
-<script src="https://unpkg.com/xior@0.4.0/plugins/error-retry.umd.js"></script>
+<script src="https://unpkg.com/xior@0.4.1/plugins/error-retry.umd.js"></script>
 
 <!-- Usage -->
 <script>
@@ -771,9 +771,9 @@ Use CDN:
 Using jsDelivr CDN:
 
 ```html
-<script src="https://cdn.jsdelivr.net/npm/xior@0.4.0/dist/xior.umd.js"></script>
+<script src="https://cdn.jsdelivr.net/npm/xior@0.4.1/dist/xior.umd.js"></script>
 <!-- Load plugin -->
-<script src="https://cdn.jsdelivr.net/npm/xior@0.4.0/plugins/throttle.umd.js"></script>
+<script src="https://cdn.jsdelivr.net/npm/xior@0.4.1/plugins/throttle.umd.js"></script>
 
 <!-- Usage -->
 <script>
@@ -786,10 +786,10 @@ Using jsDelivr CDN:
 Using unpkg CDN:
 
 ```html
-<script src="https://unpkg.com/xior@0.4.0/dist/xior.umd.js"></script>
+<script src="https://unpkg.com/xior@0.4.1/dist/xior.umd.js"></script>
 
 <!-- Load plugin -->
-<script src="https://unpkg.com/xior@0.4.0/plugins/throttle.umd.js"></script>
+<script src="https://unpkg.com/xior@0.4.1/plugins/throttle.umd.js"></script>
 
 <!-- Usage -->
 <script>
@@ -844,9 +844,9 @@ Use CDN:
 Using jsDelivr CDN:
 
 ```html
-<script src="https://cdn.jsdelivr.net/npm/xior@0.4.0/dist/xior.umd.js"></script>
+<script src="https://cdn.jsdelivr.net/npm/xior@0.4.1/dist/xior.umd.js"></script>
 <!-- Load plugin -->
-<script src="https://cdn.jsdelivr.net/npm/xior@0.4.0/plugins/dedupe.umd.js"></script>
+<script src="https://cdn.jsdelivr.net/npm/xior@0.4.1/plugins/dedupe.umd.js"></script>
 
 <!-- Usage -->
 <script>
@@ -859,10 +859,10 @@ Using jsDelivr CDN:
 Using unpkg CDN:
 
 ```html
-<script src="https://unpkg.com/xior@0.4.0/dist/xior.umd.js"></script>
+<script src="https://unpkg.com/xior@0.4.1/dist/xior.umd.js"></script>
 
 <!-- Load plugin -->
-<script src="https://unpkg.com/xior@0.4.0/plugins/dedupe.umd.js"></script>
+<script src="https://unpkg.com/xior@0.4.1/plugins/dedupe.umd.js"></script>
 
 <!-- Usage -->
 <script>
@@ -924,9 +924,9 @@ Use CDN:
 Using jsDelivr CDN:
 
 ```html
-<script src="https://cdn.jsdelivr.net/npm/xior@0.4.0/dist/xior.umd.js"></script>
+<script src="https://cdn.jsdelivr.net/npm/xior@0.4.1/dist/xior.umd.js"></script>
 <!-- Load plugin -->
-<script src="https://cdn.jsdelivr.net/npm/xior@0.4.0/plugins/error-cache.umd.js"></script>
+<script src="https://cdn.jsdelivr.net/npm/xior@0.4.1/plugins/error-cache.umd.js"></script>
 
 <!-- Usage -->
 <script>
@@ -939,10 +939,10 @@ Using jsDelivr CDN:
 Using unpkg CDN:
 
 ```html
-<script src="https://unpkg.com/xior@0.4.0/dist/xior.umd.js"></script>
+<script src="https://unpkg.com/xior@0.4.1/dist/xior.umd.js"></script>
 
 <!-- Load plugin -->
-<script src="https://unpkg.com/xior@0.4.0/plugins/error-cache.umd.js"></script>
+<script src="https://unpkg.com/xior@0.4.1/plugins/error-cache.umd.js"></script>
 
 <!-- Usage -->
 <script>
@@ -1087,9 +1087,9 @@ Use CDN:
 Using jsDelivr CDN:
 
 ```html
-<script src="https://cdn.jsdelivr.net/npm/xior@0.4.0/dist/xior.umd.js"></script>
+<script src="https://cdn.jsdelivr.net/npm/xior@0.4.1/dist/xior.umd.js"></script>
 <!-- Load plugin -->
-<script src="https://cdn.jsdelivr.net/npm/xior@0.4.0/plugins/progress.umd.js"></script>
+<script src="https://cdn.jsdelivr.net/npm/xior@0.4.1/plugins/progress.umd.js"></script>
 
 <!-- Usage -->
 <script>
@@ -1102,10 +1102,10 @@ Using jsDelivr CDN:
 Using unpkg CDN:
 
 ```html
-<script src="https://unpkg.com/xior@0.4.0/dist/xior.umd.js"></script>
+<script src="https://unpkg.com/xior@0.4.1/dist/xior.umd.js"></script>
 
 <!-- Load plugin -->
-<script src="https://unpkg.com/xior@0.4.0/plugins/progress.umd.js"></script>
+<script src="https://unpkg.com/xior@0.4.1/plugins/progress.umd.js"></script>
 
 <!-- Usage -->
 <script>
@@ -1212,9 +1212,9 @@ Use CDN:
 Using jsDelivr CDN:
 
 ```html
-<script src="https://cdn.jsdelivr.net/npm/xior@0.4.0/dist/xior.umd.js"></script>
+<script src="https://cdn.jsdelivr.net/npm/xior@0.4.1/dist/xior.umd.js"></script>
 <!-- Load plugin -->
-<script src="https://cdn.jsdelivr.net/npm/xior@0.4.0/plugins/mock.umd.js"></script>
+<script src="https://cdn.jsdelivr.net/npm/xior@0.4.1/plugins/mock.umd.js"></script>
 
 <!-- Usage -->
 <script>
@@ -1227,10 +1227,10 @@ Using jsDelivr CDN:
 Using unpkg CDN:
 
 ```html
-<script src="https://unpkg.com/xior@0.4.0/dist/xior.umd.js"></script>
+<script src="https://unpkg.com/xior@0.4.1/dist/xior.umd.js"></script>
 
 <!-- Load plugin -->
-<script src="https://unpkg.com/xior@0.4.0/plugins/mock.umd.js"></script>
+<script src="https://unpkg.com/xior@0.4.1/plugins/mock.umd.js"></script>
 
 <!-- Usage -->
 <script>
@@ -1319,6 +1319,7 @@ import {
   isAbsoluteURL,
   joinPath,
   isXiorError,
+  trimUndefined,
 } from 'xior';
 ```
 
diff --git a/package.json b/package.json
index ed01741..b389f72 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "xior",
-  "version": "0.4.0",
+  "version": "0.4.1",
   "description": "A lite request lib based on fetch with plugin support and similar API to axios.",
   "repository": "suhaotian/xior",
   "bugs": "https://github.com/suhaotian/xior/issues",
diff --git a/src/interceptors.ts b/src/interceptors.ts
index 40c4f42..f522e68 100644
--- a/src/interceptors.ts
+++ b/src/interceptors.ts
@@ -2,6 +2,7 @@
 import { encodeParams, merge } from 'xior/utils';
 
 import type { XiorInterceptorRequestConfig } from './types';
+import { trimUndefined } from './utils';
 
 const appPrefix = 'application/';
 const formUrl = `${appPrefix}x-www-form-urlencoded`;
@@ -45,7 +46,7 @@ export default async function defaultRequestInterceptor(req: XiorInterceptorRequ
       newParams = merge({}, data || {}, newParams);
     }
     if (contentType === jsonType) {
-      _data = JSON.stringify(data);
+      _data = JSON.stringify(trimUndefined(data));
     } else if (!isGet && contentType === formUrl && data && typeof data === 'object') {
       _data = paramsSerializer(data);
     }
diff --git a/src/plugins/token-refresh.ts b/src/plugins/token-refresh.ts
new file mode 100644
index 0000000..aa6f0e8
--- /dev/null
+++ b/src/plugins/token-refresh.ts
@@ -0,0 +1,73 @@
+import xior, { XiorError as AxiosError, XiorInstance, XiorResponse } from 'xior';
+import errorRetry from 'xior/plugins/error-retry';
+
+const http = xior.create();
+
+http.plugins.use(
+  errorRetry({
+    enableRetry: (config, error) => {
+      if (error.response && shouldRefreshToken(error.response)) {
+        return true;
+      }
+    },
+  })
+);
+setupTokenRefresh(
+  http,
+  // eslint-disable-next-line node/handle-callback-err
+  async (error) => {
+    const { data } = await http.post('/new/token');
+    if (data.token) {
+      // Set new token here
+      // localStorage.setItem('TOKEN', token);
+      // or
+      // http.defaults.headers['Authorization'] = `Beare ${data.token}`;
+    } else {
+      return Promise.reject(new Error('Wrong token'));
+    }
+  },
+  {
+    shouldRefresh(response) {
+      return Boolean(response?.status && [401, 403].includes(response.status));
+    },
+  }
+);
+
+export function shouldRefreshToken(response: XiorResponse) {
+  return response?.status && [401].includes(response.status);
+}
+export default function setupTokenRefresh(
+  instance: XiorInstance,
+  getToken: (error: AxiosError) => Promise<any>,
+  options?: {
+    shouldRefresh: (response: XiorResponse) => boolean;
+  }
+) {
+  const shouldRefresh = options?.shouldRefresh || shouldRefreshToken;
+
+  let refreshingToken = false;
+  const queue: (() => void)[] = [];
+  instance.interceptors.response.use(
+    async (response) => {
+      return response;
+    },
+    async (error: AxiosError) => {
+      if (error?.response && shouldRefresh(error.response)) {
+        if (refreshingToken) {
+          await new Promise<void>((resolve) => {
+            queue.push(resolve);
+          });
+        } else {
+          refreshingToken = true;
+          try {
+            await getToken(error);
+          } finally {
+            refreshingToken = false;
+            queue.forEach((r) => r());
+          }
+        }
+      }
+      return Promise.reject(error);
+    }
+  );
+}
diff --git a/src/utils.ts b/src/utils.ts
index 7a9542f..6f1fb28 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -4,33 +4,36 @@ export * from './any-signals';
 export * from './merge';
 export * from './plugins/utils';
 
+const undefinedValue = undefined;
 export function encodeParams<T = any>(
   params: T,
   encodeURI = true,
   parentKey: string | null = null
 ): string {
-  if (params === undefined || params === null) return '';
+  if (params === undefinedValue || params === null) return '';
   const encodedParams = [];
   const encodeURIFunc = encodeURI ? encodeURIComponent : (v: string) => v;
 
   for (const key in params) {
     if (Object.prototype.hasOwnProperty.call(params, key)) {
       const value = (params as any)[key];
-      const encodedKey = parentKey ? `${parentKey}[${encodeURIFunc(key)}]` : encodeURIFunc(key);
+      if (value !== undefinedValue) {
+        const encodedKey = parentKey ? `${parentKey}[${encodeURIFunc(key)}]` : encodeURIFunc(key);
 
-      if (typeof value === 'object') {
-        // If the value is an object or array, recursively encode its contents
-        const result = encodeParams(value, encodeURI, encodedKey);
-        if (result !== '') encodedParams.push(result);
-      } else if (Array.isArray(value)) {
-        // If the value is an array, encode each element individually
-        value.forEach((element, index) => {
-          const arrayKey = `${encodedKey}[${index}]`;
-          encodedParams.push(`${encodeURIFunc(arrayKey)}=${encodeURIFunc(element)}`);
-        });
-      } else {
-        // Otherwise, encode the key-value pair
-        encodedParams.push(`${encodeURIFunc(encodedKey)}=${encodeURIFunc(value)}`);
+        if (typeof value === 'object') {
+          // If the value is an object or array, recursively encode its contents
+          const result = encodeParams(value, encodeURI, encodedKey);
+          if (result !== '') encodedParams.push(result);
+        } else if (Array.isArray(value)) {
+          // If the value is an array, encode each element individually
+          value.forEach((element, index) => {
+            const arrayKey = `${encodedKey}[${index}]`;
+            encodedParams.push(`${encodeURIFunc(arrayKey)}=${encodeURIFunc(element)}`);
+          });
+        } else {
+          // Otherwise, encode the key-value pair
+          encodedParams.push(`${encodeURIFunc(encodedKey)}=${encodeURIFunc(value)}`);
+        }
       }
     }
   }
@@ -38,6 +41,22 @@ export function encodeParams<T = any>(
   return encodedParams.join('&');
 }
 
+export function trimUndefined(obj: any): any {
+  if (Array.isArray(obj)) {
+    return obj.map(trimUndefined);
+  } else if (obj && typeof obj === 'object') {
+    Object.keys(obj).forEach((key) => {
+      const value = obj[key];
+      if (value === undefinedValue) {
+        delete obj[key];
+      } else {
+        return trimUndefined(value);
+      }
+    });
+  }
+  return obj;
+}
+
 /**
  * Determines whether the specified URL is absolute
  *
diff --git a/src/xior.ts b/src/xior.ts
index 34a4e6b..bb24dbf 100644
--- a/src/xior.ts
+++ b/src/xior.ts
@@ -20,8 +20,8 @@ import type {
   XiorResponseInterceptorConfig,
 } from './types';
 
-const supportAbortController = typeof AbortController !== 'undefined';
 const undefinedValue = undefined;
+const supportAbortController = typeof AbortController !== `${undefinedValue}`;
 export type XiorInstance = xior;
 
 async function getResponseData(
@@ -49,7 +49,7 @@ export class xior {
   static create(options?: XiorRequestConfig): XiorInstance {
     return new xior(options);
   }
-  static VERSION = '0.4.0';
+  static VERSION = '0.4.1';
 
   config?: XiorRequestConfig;
   defaults: XiorInterceptorRequestConfig;
diff --git a/tests/src/tests/encode-params.test.ts b/tests/src/tests/encode-params-data.test.ts
similarity index 58%
rename from tests/src/tests/encode-params.test.ts
rename to tests/src/tests/encode-params-data.test.ts
index 6f8b287..c60122a 100644
--- a/tests/src/tests/encode-params.test.ts
+++ b/tests/src/tests/encode-params-data.test.ts
@@ -53,4 +53,40 @@ describe('encodeParams()', function () {
     assert.strictEqual(stringify(data.query), stringify(params));
     assert.strictEqual(stringify(data.query), encodeParams(params));
   });
+
+  it('encode object should remove undefined value', () => {
+    const data = { a: '1', c: undefined };
+    assert.strictEqual(encodeParams(data), `a=1`);
+  });
+
+  it('encode nested object should remove undefined value', () => {
+    const data = { a: '1', d: { c: undefined } };
+    assert.strictEqual(encodeParams(data), `a=1`);
+  });
+
+  it('encode nested object should work exactly with server(remove undefined value)', async () => {
+    const instance = xior.create({
+      baseURL,
+      paramsSerializer: encodeParams,
+    });
+    const params = { a: 'b', c: undefined, d: { e: undefined } };
+    const { data } = await instance.get('/get', { params });
+    assert.strictEqual(data.query.hasOwnProperty('a'), true);
+    assert.strictEqual(data.query['a'], 'b');
+    assert.strictEqual(data.query.hasOwnProperty('c'), false);
+    assert.strictEqual(data.query.hasOwnProperty('d'), false);
+  });
+
+  it('nested data object should work exactly with server(remove undefined value)', async () => {
+    const instance = xior.create({
+      baseURL,
+      paramsSerializer: encodeParams,
+    });
+    const objData = { a: 'b', c: undefined, d: { e: undefined } };
+    const { data } = await instance.post('/post', objData);
+    assert.strictEqual(data.body.hasOwnProperty('a'), true);
+    assert.strictEqual(data.body['a'], 'b');
+    assert.strictEqual(data.body.hasOwnProperty('c'), false);
+    assert.strictEqual(data.body['d'].hasOwnProperty('e'), false);
+  });
 });
diff --git a/tests/src/tests/utils.test.ts b/tests/src/tests/utils.test.ts
index 7b1e460..b3f396b 100644
--- a/tests/src/tests/utils.test.ts
+++ b/tests/src/tests/utils.test.ts
@@ -7,6 +7,7 @@ import {
   isAbsoluteURL,
   isXiorError,
   joinPath,
+  trimUndefined,
 } from 'xior';
 
 describe('utils tests', () => {
@@ -56,4 +57,30 @@ describe('utils tests', () => {
       assert.strictEqual(isXiorError(error), false);
     });
   });
+
+  describe('utils.trimUndefined tests', () => {
+    it('should work with `null`', () => {
+      const result = trimUndefined(null);
+      assert.strictEqual(result, null);
+    });
+    it('should work with `undefined`', () => {
+      const result = trimUndefined(undefined);
+      assert.strictEqual(result, undefined);
+    });
+    it('should work with `{a: 1, b: undefined}`', () => {
+      const result = trimUndefined({ a: 1, b: undefined });
+      assert.strictEqual(result.hasOwnProperty('a'), true);
+      assert.strictEqual(result.hasOwnProperty('b'), false);
+      assert.strictEqual(result['a'], 1);
+    });
+    it('should work with nested `{a: 1, b: undefined, c: {d: {e: undefined}}}`', () => {
+      const result = trimUndefined({ a: 1, b: undefined, c: { d: { e: undefined } } });
+      assert.strictEqual(result.hasOwnProperty('b'), false);
+      assert.strictEqual(result.hasOwnProperty('a'), true);
+      assert.strictEqual(result['a'], 1);
+      assert.strictEqual(result.hasOwnProperty('c'), true);
+      assert.strictEqual(result['c'].hasOwnProperty('d'), true);
+      assert.strictEqual(result['c']['d'].hasOwnProperty('e'), false);
+    });
+  });
 });