function _openPath(treeData, path) {
        var objectPath = _filePathToObjectPath(treeData, path);

        function setOpen(node) {
            return node.set("open", true);
        }

        while (objectPath && objectPath.length) {
            var node = treeData.getIn(objectPath);
            if (isFile(node)) {
                objectPath.pop();
            } else {
                if (!node.get("open")) {
                    treeData = treeData.updateIn(objectPath, setOpen);
                }
                objectPath.pop();
                if (objectPath.length) {
                    objectPath.pop();
                }
            }
        }

        return treeData;
    }
@private

Opens the directories along the provided path.

@param {Immutable.Map} treeData
@param {string} path Path to open