content: 
  import React, { Component } from 'react';
  import { SliderField, Gauge, FormPanel } from '@extjs/ext-react';
  
  export default class GaugeExample extends Component {
  
      constructor() {
          super();
          this.state = {
              value: 40
          }
      }
  
      updateGauges(slider, value) {
          this.setState({ value })
      }
  
      render() {
          const { value } = this.state;
  
          return (
              <FormPanel shadow layout="vbox" maxWidth={350}>
                  <SliderField label="Value" onChange={this.updateGauges.bind(this)} value={value}/>
                  <Gauge flex={1} value={value}/>
                  <Gauge flex={1} value={value} ui="green" trackStart={180} trackLength={360}/>
              </FormPanel>
          )
      }
  
  }