content: import React from 'react';
  
  const UNITS = [{
    name: 'km/h',
    conversionFromMeterPerSecond: 3.6,
  }, {
    name: 'm/s',
    conversionFromMeterPerSecond: 1,
  }, {
    name: 'mph',
    conversionFromMeterPerSecond: 2.23694,
  }];
  
  export default class Speedometer extends React.Component {
    constructor(props) {
      super(props);
  
      this.state = {
        unit: 0,
      };
  
      this.changeUnit = this.changeUnit.bind(this);
    }
  
    changeUnit() {
      this.setState({
        unit: (this.state.unit + 1) % UNITS.length,
      });
    }
  
    render() {
      const { meterPerSecond } = this.props;
  
      const currUnit = UNITS[this.state.unit];
      const name = currUnit.name;
      const read = Math.round(meterPerSecond * currUnit.conversionFromMeterPerSecond);
  
      return (
              <span onClick={this.changeUnit}>
                  <span className="speed-read">{read}</span>
                  <span className="speed-unit">{name}</span>
              </span>
      );
    }
  }
  