Openlayers 3 - 如何垃圾收集 Canvas ReplayGroup 对象？

Question

I've got an issue with ol.render.canvas.ReplayGroup objects not being let go to garbage collection.

The layer that this is for is an ol.layer.Image, created from an ol.source.ImageVector, in turn created from an ol.source.Vector source.

The sequence of events that I'd like to have result in some garbage collection is, the Image's style is set to null with setStyle(null); then the Image's source is set to null with setSource(null); then the ol.layer.Image object is removed from the map with setMap(null);

This does result in the layer being removed from the map ( I think, it disappears ), but when I profile the web page with Chrome's heap allocation profile, the canvas.ReplayGroup object is still there, never to be used again.

Is this something anyone else has run into? I've tried to use the map.addLayer() instead of layer.setMap( ), same results.

== edit ==

I forgot to write, the ol.layer.Image has been added to an ol.layer.Group. More specifically, that last part above was map.addLayer( group ) and also group.getLayers().forEach(function(l){ l.setMap(map); }), no difference it seems.

Answer 1

https://github.com/openlayers/ol3/blob/master/src/ol/source/imagevectorsource.js

In the ol.source.ImageVector that's the source for the ol.layer.Image, I found a reference to the replay group classes called replayGroup_. Setting that 'private' property to null after setting the layer source to null results in garbage collection.. yay!

var imageVector = layer.getSource();
layer.setSource(null);
imageVector.setStyle(null);
imageVector.replayGroup_ = null;
imageVector = null;

This works for me for now