Method _removeUnreferencedMetasets

src/core/core.controller.js:403–413

* @private

()

	 * @private
	 */
  _removeUnreferencedMetasets() {
    const {_metasets: metasets, data: {datasets}} = this;
    if (metasets.length > datasets.length) {
      delete this._stacks;
    }
    metasets.forEach((meta, index) => {
      if (datasets.filter(x => x === meta._dataset).length === 0) {
        this._destroyDatasetMeta(index);
      }
    });
  }

  buildOrUpdateControllers() {
    const newControllers = [];