How to use the matrix-js-sdk.Room function in matrix-js-sdk

if (!data) return null;

        var obj1 = JSON.parse(data);
        var obj2 = JSON.parse(data);

        var stateEvents = [];
        var oldStateEvents = [];
        for (var eventType in obj1.state.events) {
            var event = obj1.state.events[eventType];
            for (var skey in event) {
                stateEvents.push(new MatrixEvent(obj1.state.events[eventType][skey]));
                oldStateEvents.push(new MatrixEvent(obj2.state.events[eventType][skey]));
            }
        }

        var room = new Room(roomId, {
            storageToken: "voyager"
        });
        room.oldState.setStateEvents(oldStateEvents);
        room.currentState.setStateEvents(stateEvents);

        this._registerRoomListeners(room);

        return room;
    }