我创建了带有Material UI的react js项目

然后我用

build": "./node_modules/.bin/babel src --out-file BuildTest/index.js 

在客户端（其他项目）中安装此模块时，出现此问题：

模块：

import React from 'react';
import PropTypes from 'prop-types';
import { withStyles } from '@material-ui/core/styles';
import Button from '@material-ui/core/Button';

const styles = {
  root: {
    background: 'linear-gradient(45deg,#FE6B8B 30%,#FF8E53 90%)',border: 0,borderRadius: 3,boxShadow: '0 3px 5px 2px rgba(255,105,135,.3)',color: 'white',height: 48,padding: '0 30px',},};

function HigherOrderComponent(props) {
  const { classes } = props;
  return <Button classname={classes.root}>Higher-order component</Button>;
}

HigherOrderComponent.propTypes = {
  classes: PropTypes.object.isrequired,};

export default withStyles(styles)(HigherOrderComponent);

客户端：

import Mtest from "testmodule";
import React,{ Component } from "react";


export default class App extends Component {
  render() {
    return (
      <div>
         <Mtest/>
      </div>
    )
  }
}