[4.2.0.265] TreeStore.onBeforeExpand

[christophe.geiser]

Took me a while to find the culprit.

Few thing with this method:

1- the return value of (node.raw || node[node.persistenceProperty])[(reader = me.getProxy().getReader()).root]) is likely to be "true". You then try to evaluate me.fillNode(node, reader.extractData(true)), which does not make a lot of sense (we should have childNodes instead here).
2- As the return value of above is truthly, elseif (node.isLoading()) {... is never called. That can be problematic - at least was with my code.
3- With the current configuation, sames nodes can be loaded multiple times. We might need a return if node.isLoaded()

    onBeforeNodeExpand: function(node, callback, scope) {
        var me = this,
            reader, dataRoot, data;

        // Children are loaded go ahead with expand
        if (node.isLoaded()) {
            Ext.callback(callback, scope || node, [node.childNodes]);
        } else if (node.childRecords) {

        }
        // There are unloaded child nodes in the raw data because of the lazy configuration, load them then call back.
        else if (dataRoot = (data = (node.raw || node[node.persistenceProperty])[(reader = me.getProxy().getReader()).root])) {
            me.fillNode(node, reader.extractData(dataRoot));
            delete data[reader.root];
            Ext.callback(callback, scope || node, [node.childNodes]);
        }
        //else if (node.isLoading()) {
if (node.isLoading()) {
            me.on('load', function() {
                Ext.callback(callback, scope || node, [node.childNodes]);
            }, me, {single: true});
        }
        else {
            me.read({
                node: node,
                callback: function() {
                    // Clear the callback, since if we're introducing a custom one,
                    // it may be re-used on reload
                    delete me.lastOptions.callback;
                    Ext.callback(callback, scope || node, [node.childNodes]);
                }
            });
        }
    },

[mitchellsimoens]

Can I get a runnable test case?