[MarkerClusterer] Repaints the map for every marker to add / remove

[amangeot]

Hello,
I think this issue still exists in v6: #210

The issue is that MarkerClusterer is passed down to Markers within the context, so that Marker can add itself to the MarkerClusterer. Then the underlying addMarker or removeMarker forces a redraw on the map, for each added or removed marker.

From Marker.js:
In getInitialState(): markerClusterer.addMarker(marker);
In componentWillUnmount(): markerClusterer.removeMarker(marker)

Now from markerclustererplus.js:

MarkerClusterer.prototype.addMarker = function (marker, opt_nodraw) {
  this.pushMarkerTo_(marker);
  if (!opt_nodraw) {
    this.redraw_();
  }
}

Not sure to be competent enough for this job, but I'll try my best to add a pull request that solves this issue.

[amangeot]

I forked the project and edited these two lines in Marker.js to prevent every added / removed Markers from redrawing clusters:
In getInitialState(): markerClusterer.addMarker(marker, true);
In componentWillUnmount(): markerClusterer.removeMarker(marker, true)`

[tomchentw]

Please refer to Getting Help section in the README (or #469).