yarn add qrcode.react
// or 
npm install qrcode.react --save

import QRCode from ‘qrcode.react‘;

<QRCode
    id="qrCode"
    value="https://www.jianshu.com/u/992656e8a8a6"
    size={200} // 二维码的大小
    fgColor="#000000" // 二维码的颜色
    style={{ margin: ‘auto‘ }}
    imageSettings={{ // 二维码中间的logo图片
        src: ‘logoUrl‘,
        height: 100,
        width: 100,
        excavate: true, // 中间图片所在的位置是否镂空
     }}
 />        

<a id="down_link" onClick={this.changeCanvasToPic}>
    点击下载
</a>

 changeCanvasToPic = () => {
    const canvasImg = document.getElementById(‘qrCode‘); // 获取canvas类型的二维码
    const img = new Image();
    img.src = canvasImg.toDataURL(‘image/png‘); // 将canvas对象转换为图片的data url
    const downLink = document.getElementById(‘down_link‘);
    downLink.href = img.src;
    downLink.download = ‘二维码‘; // 图片name
  };