Gmaps zoom_changed

demo.js

import React from 'react';
import ReactDOM from 'react-dom';
import { Gmaps } from 'react-gmaps';

const App = React.createClass({

  handleZoomChanged() {
    console.log('zoom:', this.refs.Gmaps.getMap().getZoom());
  },

  render() {
    return (
      <Gmaps
        height={300}
        lat={51.5258541}
        lng={-0.08040660000006028}
        onZoomChanged={this.handleZoomChanged}
        ref="Gmaps"
        width={400}
        zoom={12}
      />
    );
  }

});

ReactDOM.render(<App />, document.getElementById('gmaps'));