fix(core):修复正则匹配是否引入React

Author: SunLxy

core/src/utils/transform.ts

@@ -8,11 +8,11 @@ export function babelTransform(input: string, filename: string) {
 }
 
 export const getTransformValue = (str: string, filename: string, funName: string) => {
-  const isReact = /import React.+from ("|')react("|')/.test(str);
+  const isReact = /import\x20+React(\x20+|[\x20+,]+({[a-zA-Z0-9,\s]+}|{})\x20+)from\x20+('|")react('|")/.test(str);
   // 先判断 是否引入 react
   const tran = isReact ? str : `import React from "react"\n ${str}`;
   /** 先把默认导出 export default 进行替换 **/
-  const newCode = `${tran.replace('export default', 'const _default = ')}\n`;
+  const newCode = `${tran.replace(/export\x20+default/, 'const _default = ')}\n`;
   const code = `${babelTransform(newCode, `${filename}`).code}\n return _react["default"].createElement(_default)`;
 
   return `function ${funName}(){

website/src/pages/example/App.md

@@ -11,11 +11,14 @@ import { Alert } from "uiw";
 // or
 import Alert from "@uiw/react-alert";
 ```
-
+`import React from 'react'`
 ## Basic Usage
 
 ```jsx mdx:preview
-import React from "react";
+import React,{ 
+  useState,
+  useEffect,
+} from "react";
 import ReactDOM from "react-dom";
 import { Alert, ButtonGroup, Button } from "uiw";