source clear BUG in OpenLayers 3

Question

I'm using OpenLayers 3 (v3.20). What I want to achieve is just to remove all features from a particular layer. I see that there is a clear method and documentation says, that

clear(opt_fast)

Remove all features from the source.

However, when I apply it to my layer source like so:

layer.getSource().clear();

I see a blink (features are removed) and then I see a server request, so that features are reloaded again. So, either documentation is incomplete, or there is a bug.

I also tried to remove features like so:

features = source.getFeatures();
for (i = 0; i < features.length; i += 1) {
    source.removeFeature(features[i]);
}

But it works really strange. If, for example, I have four features, when I loop once, it removes just two features and when I loop twice, one extra feature is removed. All in all, I have to loop three times (which is indeed not DRY) to remove all features. I really wonder, why is that and how can I fix it. Thanks!

Answer 1

As pointed by Karl-Johan Sjögren, removing a array member when iterate through it modifies the array itself, so, you use reverse array or use a native function from Array MDN reference :

features = source.getFeatures();
features.forEach(function (feature){
  source.removeFeature(feature);
});