code: function () {
      this.controllerPresent = false;
      this.isControllerPresent = trackedControlsUtils.isControllerPresent; // to allow mock
      this.buttonStates = {};
      this.previousAxis = [];
      this.onModelLoaded = bind(this.onModelLoaded, this);
      this.checkIfControllerPresent = bind(this.checkIfControllerPresent, this);
      this.onGamepadConnected = bind(this.onGamepadConnected, this);
      this.onGamepadDisconnected = bind(this.onGamepadDisconnected, this);
    }
docs: Called once when component is attached. Generally for initial setup.