react-google-maps: how to use fitBounds, panBy, panTo, panToBounds public APIs?

Question

According to the React Google Maps library, you can call these four methods from the ref object.

What seems weird, is that these methods are supposed to receive two parameters, a map instance and other arguments, like so:

fitBounds(map, args) { return map.fitBounds(...args); }

However, when calling fitBounds() this way, nothing happens on the map, no bounds are changed and no errors are thrown. This is the way I have structured the component, calling fitBounds in componentDidUpdate:

import React from 'react'
import { withGoogleMap, GoogleMap, InfoWindow, Marker, OverlayView } from 'react-google-maps'
import InfoBox from 'react-google-maps/lib/addons/InfoBox'
import map from 'lodash/map'

// Higher-Order Component
const AllocatedPlacesMap = withGoogleMap(props => (
  <GoogleMap
    center={props.center}
    defaultZoom={4}
    options={{ scrollwheel: false, minZoom: 3, maxZoom: 15 }}
    onCenterChanged={props.onCenterChanged}
    ref={props.onMapMounted}>
    {props.markers.map((marker, index) => (
      <Marker
        key={index}
        position={marker.position}
      />
    ))}
  </GoogleMap>
));

class Map extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
    };
  }

  getCenter = () => {
    this._bounds = new google.maps.LatLngBounds();

    this.props.markers.forEach((marker, index) => {
      const position = new google.maps.LatLng(marker.lat, marker.lng);
      this._bounds.extend(position);
    });

    return this._bounds.getCenter();
  }

  componentDidUpdate() {
    this._map.fitBounds(this._map, this._bounds);
  }

  handleMapMounted = (map) => {
    this._map = map;
  }

  render() {
    return (
      <div className="allocated-places">
        <AllocatedPlacesMap
          containerElement={
            <div style={{ height: `100%` }} />
          }
          mapElement={
            <div style={{ height: `100%` }} />
          }
          center={this.getCenter()}
          markers={props.markers}
          onMapMounted={this.handleMapMounted}
        />
      </div>
    )
  }
}

export default Map;

Any idea of what is the correct way to call fitBounds() in this case? documentation and examples seem to be lacking in this regard.

Solution

Looking at the function definition fitBounds(map, args) { return map.fitBounds(...args); } we can see that the spread operator is applied on args. That suggests that the args should be an array.

So, in your code the second parameter should be of an array type:

this._map.fitBounds(this._map, [this._bounds]);

You can also include the second element of the array that will be transformed into the second optional parameter padding of the Maps JavaScript API fitBound() method.

this._map.fitBounds(this._map, [this._bounds, 100]);

Hope this helps!