ReactNativeでQRコード生成

import React from 'react';
import PropTypes from 'prop-types';
import { Image } from 'react-native';
import qrcode from 'qrcode-generator';

export default class QRCode extends React.PureComponent {
  constructor(props) {
    super(props);
    this.state = {
      size: null
    };
    this.onLayout = this.onLayout.bind(this);
  }

  componentWillReceiveProps(nextProps, nextContext) {
    if (nextProps.size !== this.props.size) {
      this.setState({
        size: null
      });
    }
  }

  onLayout(e) {
    const { width } = e.nativeEvent.layout;
    if (this.state.size !== width) {
      this.setState({ size: width });
    }
  }

  render() {
    const { data, cellSize, margin, typeNumber, errorCorrectionLevel } = this.props;
    const size = this.state.size || this.props.size;
    const QRCode = qrcode(typeNumber, errorCorrectionLevel);
    QRCode.addData(data);
    QRCode.make();
    let calculatedCellSize = cellSize;
    if (typeof calculatedCellSize !== 'number' && typeof size === 'number') {
      calculatedCellSize = typeof margin === 'number' ? Math.round((size - margin * 2) / QRCode.getModuleCount())
        : Math.round(size / (QRCode.getModuleCount() + 8));
    }
    const uri = QRCode.createDataURL(calculatedCellSize, margin);
    return (
      <Image
        key={uri}
        onLayout={this.onLayout}
        style={{
          width: size,
          aspectRatio: 1
        }}
        source={{ uri }}
      />
    );
  }
}

QRCode.defaultProps = {
  typeNumber: 0 // 自動
};

QRCode.propTypes = {
  data: PropTypes.string.isRequired, // データ文字列
  size: PropTypes.oneOfType([PropTypes.number, PropTypes.string]).isRequired, // 画像の大きさ
  cellSize: PropTypes.number, // セルの大きさ
  margin: PropTypes.number, // 余白の大きさ
  typeNumber: PropTypes.number, // 型番
  errorCorrectionLevel: PropTypes.string.isRequired // 誤り訂正レベル
};