Recursively find a tree item
function (tId, partialTree) {
            if (tId === void 0) { tId = ''; }
            if (partialTree === void 0) { partialTree = tree; }
            if (!tId) {
                return undefined;
            }
            var found;
            partialTree.some(function (treeItem) {
                if (treeItem[id] === tId) {
                    found = treeItem;
                    return true;
                }
                found = treeItem[children] ? find(tId, treeItem[children]) : undefined;
                return found ? true : false;
            });
            return found;
        }