Animated Cluster - Unable to get property of '0' of undefined or null reference

[wlerner]

If the extent is changed too quickly (i.e., a user zooms in and out rapidly) when there are clusters displayed on the map, an error can sometimes be generated. There does not appear to be any code to check if the features length is undefined.

Unable to get property '0' of undefined or null reference

The error occurs at line 57 in animatedclusterlayer.js section below:

/** @private Get the cluster that contains a feature
*/
ol.layer.AnimatedCluster.prototype.getClusterForFeature = function(f, cluster)
{   for (var j=0, c; c=cluster[j]; j++)
    {   var features = cluster[j].get('features');
        //if (features.length > 1) 
        for (var k=0, f2; f2=features[k]; k++)   <== Error Here
        {   if (f===f2) 
            {   return cluster[j];
            }
        }
    }
    return false;
}

This error can be reproduced under Google Chrome and Internet Explorer.

[Viglino]

Right! I've added a test to verify the integrity of the cluster.
Thanks for reporting this bug.

[wlerner]

The length verification fix above works wonderfully. There is another section of code where this error is now occurring.

Unable to get property '0' of undefined or null reference

The error occurs at line 101 in animatedclusterlayer.js section below:

        for (var i=0, c0; c0=a.cA[i]; i++)
        {   var f = c0.get('features')[0];     <== Error Here
            var c = this.getClusterForFeature (f, a.cB);
            if (c) a.clusters.push({ f:c0, pt:c.getGeometry().getCoordinates() });
        }

This error can be reproduced under Google Chrome, Firefox 42, and Internet Explorer 11.
Thanks for looking into this issue.

[Viglino]

Yep! I now test if the feature is a consistent cluster.
Thanks for taking care of my bugs!

[wlerner]

You are welcome! I appreciate all of your hard work. Thank you for sharing your code and expertise with the OL3 community. The last commit solved the problem quite nicely. I will close the issue.