dgrid Tree._expandWhenInDom generating exception

[jstolte]

dgrid v1.2.1, dojo v1.13.0, dstore v1.1.1
Tree._expandWhenInDom has the following snippet at line 262...

var expandPromise = this.expand( rowElement, true, true, options.scrollingUp);
if (dfd) {
    expandPromise.then(function () {
        dfd.resolve();
    });
}

Tree.expand() starts off with the following...

if (!this._treeColumn) {
    return;
}

In my case, this._treeColumn is undefined, so this.expand() returns undefined where Tree._expandWhenInDom() is expecting a promise to be returned.

All I did to the project was update the dgrid component from 0.4.4 to 1.2.1. The dgrid instance in 0.4.4 was working fine. 1.2.1 has the problem mentioned above. I did not change anything in how the grid is being created, populated with data, and used.

The initial data populating the dstore instance does not have any child elements associated with any of the top level or parent row items... so really, there are no "rows" to "expand/collapse". No idea if that is a contributing issue to the problem or not.

For what it is worh, my naive temporary solution was to wrap the result from the call to this.expand(...) in a call to when(...).
i.e. I changed line 264 of Tree.js to

when(expandPromise).then(function () {
    ...
});

[edhager]

Thanks @jstolte!

dgrid/Tree#expand should always return a promise. I fixed it.