InfoWindow

demo.js

const coords = {
  lat: 51.5258541,
  lng: -0.08040660000006028,
};

class App extends React.Component {
  constructor(props) {
    super(props);

    this.state = {
      showInfoWindow: false,
    };

    this.handleClick = this.handleClick.bind(this);
  }

  handleClick() {
    this.setState(prevState => ({
      showInfoWindow: !prevState.showInfoWindow,
    }));
  }

  render() {
    return (
      <div>
        <Gmaps
          height={300}
          lat={coords.lat}
          lng={coords.lng}
          width={400}
          zoom={12}>
          <Marker
            lat={coords.lat}
            lng={coords.lng}
          />
          {this.state.showInfoWindow &&
            <InfoWindow
              lat={coords.lat}
              lng={coords.lng}
              pixelOffset={new google.maps.Size(0, -40)}
              onCloseClick={this.handleClick}
            />
          }
        </Gmaps>
        <button onClick={this.handleClick}>Click me!</button>
      </div>
    );
  }
};

Ah, this is what i looking for. 👍
Very helpful and thanks for your kindness man. 👍