code: function () {
      var isPresent = this.isControllerPresent(this.el.sceneEl, GAMEPAD_ID_PREFIX, {});
      if (isPresent === this.controllerPresent) { return; }
      this.controllerPresent = isPresent;
      if (isPresent) {
        this.el.addEventListener('model-loaded', this.onModelLoaded);
        this.controller = trackedControlsUtils.getGamepadsByPrefix(GAMEPAD_ID_PREFIX)[0];
        if (!this.data.model) { return; }
        this.el.setAttribute('obj-model', {
          obj: DAYDREAM_CONTROLLER_MODEL_OBJ_URL,
          mtl: DAYDREAM_CONTROLLER_MODEL_OBJ_MTL
        });
      } else {
        this.controller = null;
        this.el.removeAttribute('obj-model');
        this.el.removeEventListener('model-loaded', this.onModelLoaded);
      }
    }
docs: Called when a component is removed (e.g., via removeAttribute).
  Generally undoes all modifications to the entity.
   TODO ... remove: function () { },