diff --git a/.eslintrc.json b/.eslintrc.json
index f92d35e..01ff112 100644
--- a/.eslintrc.json
+++ b/.eslintrc.json
@@ -8,6 +8,7 @@
   "plugins": ["@typescript-eslint"],
   "root": true,
   "rules": {
-    "@typescript-eslint/no-explicit-any": 0
+    "@typescript-eslint/no-explicit-any": 0,
+    "@typescript-eslint/no-non-null-assertion": 0
   }
 }
diff --git a/global.d.ts b/global.d.ts
index 984dd3b..9c03c7c 100644
--- a/global.d.ts
+++ b/global.d.ts
@@ -7,5 +7,6 @@ declare const qq: unknown;
 declare const qh: unknown;
 declare const ks: unknown;
 declare const dd: unknown;
+declare const jd: unknown;
 
 type AnyObject<T = any> = Record<string, T>;
diff --git a/src/adapter.ts b/src/adapter.ts
index 46307ee..d6d62b5 100644
--- a/src/adapter.ts
+++ b/src/adapter.ts
@@ -140,6 +140,7 @@ export function getAdapterDefault(): AxiosAdapter | undefined {
     () => qh,
     () => ks,
     () => dd,
+    () => jd,
   ];
 
   let platform;
diff --git a/src/core/dispatchRequest.ts b/src/core/dispatchRequest.ts
index 79af25d..6c7fd64 100644
--- a/src/core/dispatchRequest.ts
+++ b/src/core/dispatchRequest.ts
@@ -17,6 +17,7 @@ export default function dispatchRequest<TData = unknown>(
 ): Promise<AxiosResponse> {
   throwIfCancellationRequested(config);
 
+  config.method = config.method ?? 'get';
   config.url = transformURL(config);
   config.headers = flattenHeaders(config);
   config.data = transformData(
diff --git a/src/core/flattenHeaders.ts b/src/core/flattenHeaders.ts
index bb8f667..2b1f6e2 100644
--- a/src/core/flattenHeaders.ts
+++ b/src/core/flattenHeaders.ts
@@ -1,10 +1,6 @@
 import { isPlainObject } from '../helpers/is';
-import { omit, toLowerCase } from '../helpers/utils';
-import {
-  AxiosRequestConfig,
-  AxiosRequestMethodAlias,
-  AxiosRequestHeaders,
-} from './Axios';
+import { omit } from '../helpers/utils';
+import { AxiosRequestConfig, AxiosRequestHeaders } from './Axios';
 
 export function flattenHeaders(
   config: AxiosRequestConfig,
@@ -15,9 +11,7 @@ export function flattenHeaders(
 
   return {
     ...(config.headers.common ?? {}),
-    ...(config.headers[
-      toLowerCase<AxiosRequestMethodAlias>(config.method, 'get')
-    ] ?? {}),
+    ...(config.headers[config.method!.toLowerCase()] ?? {}),
     ...omit(
       config.headers,
       'common',
diff --git a/src/core/generateType.ts b/src/core/generateType.ts
index 632a286..64f12ec 100644
--- a/src/core/generateType.ts
+++ b/src/core/generateType.ts
@@ -1,17 +1,16 @@
-import { toLowerCase } from '../helpers/utils';
 import { AxiosAdapterRequestType } from '../adapter';
-import { AxiosRequestConfig, AxiosRequestMethodAlias } from './Axios';
+import { AxiosRequestConfig } from './Axios';
 
 export function generateType(
   config: AxiosRequestConfig,
 ): AxiosAdapterRequestType {
   let requestType: AxiosAdapterRequestType = 'request';
-  const method = toLowerCase<AxiosRequestMethodAlias>(config.method, 'get');
 
-  if (config.upload && method === 'post') {
+  const method = config.method!.toUpperCase();
+  if (config.upload && method === 'POST') {
     requestType = 'upload';
   }
-  if (config.download && method === 'get') {
+  if (config.download && method === 'GET') {
     requestType = 'download';
   }
 
diff --git a/src/core/request.ts b/src/core/request.ts
index 2a43818..fe4bf29 100644
--- a/src/core/request.ts
+++ b/src/core/request.ts
@@ -1,5 +1,5 @@
 import { isFunction, isPlainObject } from '../helpers/is';
-import { assert, toUpperCase } from '../helpers/utils';
+import { assert } from '../helpers/utils';
 import {
   AxiosAdapterRequestConfig,
   AxiosAdapterRequestMethod,
@@ -46,7 +46,7 @@ export function request<TData = unknown>(
       ...config,
       url: config.url ?? '',
       type: generateType(config),
-      method: toUpperCase<AxiosAdapterRequestMethod>(config.method, 'GET'),
+      method: config.method!.toUpperCase() as AxiosAdapterRequestMethod,
       success,
       fail,
     };
diff --git a/src/helpers/utils.ts b/src/helpers/utils.ts
index 02a01cf..debc9cf 100644
--- a/src/helpers/utils.ts
+++ b/src/helpers/utils.ts
@@ -1,4 +1,4 @@
-import { isPlainObject, isString } from './is';
+import { isPlainObject } from './is';
 
 export function deepMerge<T extends AnyObject>(...objs: T[]): T {
   const result: AnyObject = {};
@@ -52,19 +52,3 @@ export function assert(condition: boolean, msg: string) {
 export function throwError(msg: string): void {
   throw new Error(`[axios-miniprogram]: ${msg}`);
 }
-
-export function toLowerCase<T extends string>(value: any, defaultValue: T): T {
-  if (!isString(value)) {
-    value = defaultValue;
-  }
-
-  return value.toLowerCase() as T;
-}
-
-export function toUpperCase<T extends string>(value: any, defaultValue: T): T {
-  if (!isString(value)) {
-    value = defaultValue;
-  }
-
-  return value.toUpperCase() as T;
-}
diff --git a/test/helpers/utils.test.ts b/test/helpers/utils.test.ts
index d74690a..8f6f183 100644
--- a/test/helpers/utils.test.ts
+++ b/test/helpers/utils.test.ts
@@ -5,8 +5,6 @@ import {
   omit,
   pick,
   throwError,
-  toLowerCase,
-  toUpperCase,
 } from '../../src/helpers/utils';
 
 describe('对 src/helpers/utils.ts 进行测试', () => {
@@ -49,18 +47,4 @@ describe('对 src/helpers/utils.ts 进行测试', () => {
       '[axios-miniprogram]:  msg ',
     );
   });
-
-  test('测试 toLowerCase() 是否符合预期', () => {
-    expect(toLowerCase('', 'GET')).toBe('');
-    expect(toLowerCase(undefined, 'GET')).toBe('get');
-    expect(toLowerCase('GET', '')).toBe('get');
-    expect(toLowerCase('Get', '')).toBe('get');
-  });
-
-  test('测试 toUpperCase() 是否符合预期', () => {
-    expect(toUpperCase('', 'get')).toBe('');
-    expect(toUpperCase(undefined, 'get')).toBe('GET');
-    expect(toUpperCase('get', '')).toBe('GET');
-    expect(toUpperCase('Get', '')).toBe('GET');
-  });
 });