fix circlemarker by updating equality check

[Falkyouall]

After a 2 years old discussion about this issue which tracks back to your repository, i propose a little fix that makes a lot of lifes easier.

The base of the fix lies in the CircleMarker.js file, which until now, made it impossible to render Circlemarkers inside of react-leaflet-markercluster without throwing:

TypeError: Cannot read property 'lat' of undefined.

This fix changes the equality check for the updateLeafletElement center property.

- if (toProps.center !== fromProps.center)
+ if (!latLng(toProps.center).equals(fromProps.center))

[PaulLeCam]

Hi, thanks for your PR but this should be part of your app or plugin logic.
As you can see in the CircleMarker documentation the center prop is required, if you set it to undefined as raised in the error message you quoted, it's not expected to work.

[Falkyouall]

Hi Paul,
Since im providing CircleMarker center props its rather the third party plugin. I checked the react-markercluster library, and i don't confirm any bug or mistake in there, but if you do have a idea about this issue, here is the stacktrace:

project | @ | leaflet-src.js:1612
latLngToPoint | @ | leaflet-src.js:1452
project | @ | leaflet-src.js:3834
_removeFromGridUnclustered | @ | leaflet.markercluster.js:6
_removeLayer | @ | leaflet.markercluster.js:6
removeLayer | @ | leaflet.markercluster.js:6
_moveChild | @ | leaflet.markercluster.js:6
_childMarkerMoved | @ | leaflet.markercluster.js:6
fire | @ | leaflet-src.js:588
setLatLng | @ | leaflet-src.js:7654
updateLeafletElement | @ | CircleMarker.js:31
componentDidUpdate | @ | MapLayer.js:50
componentDidUpdate | @ | Path.js:33

I don't expect you to dig into this, would greatly appreciate it tho.

[luiz-chagas]

I am running the exact same issue with the same stack trace.
For now I'm using a patched forked version of this package, hopefully the author will reconsider this PR.

[PaulLeCam]

Sorry I don't have time to investigate issues in third-party plugins.
As I wrote in the previous comment, the error seems to indicate the provided center prop is undefined, so I'd suggest you start by trying to figure out why your app or plugin is providing an undefined position and fix the problem there.