如何在react.js中创建可重用的组件或部分组件？

import React from 'react';

class CustomComponent extends React.Component {
  constructor(props) {
    super(props);
    // 初始化状态
    this.state = {
      // 状态属性
    };
  }

  render() {
    // 组件的渲染逻辑
    return (
      // JSX代码
    );
  }
}

export default CustomComponent;

import CustomComponent from './CustomComponent';

class App extends React.Component {
  render() {
    return (
      <div>
        <CustomComponent />
      </div>
    );
  }
}