text: import PropTypes from 'prop-types';
  import React from 'react';
  import mean from './dataProcessing/mean';
  import stdev from './dataProcessing/stdev';
  
  export default class SparklinesNormalBand extends React.Component {
  
      static propTypes = {
          style: PropTypes.object
      };
  
      static defaultProps = {
          style: { fill: 'red', fillOpacity: .1 }
      };
  
      render() {
  
          const { points, margin, style } = this.props;
  
          const ypoints = points.map(p => p.y);
          const dataMean = mean(ypoints);
          const dataStdev = stdev(ypoints);
  
          return (
              <rect x={points[0].x} y={dataMean - dataStdev + margin}
                  width={points[points.length - 1].x - points[0].x} height={stdev * 2}
                  style={style} />
          )
      }
  }
  