Method _getStackIndex

src/controllers/controller.bar.js:518–527

* Returns the stack index for the given dataset based on groups and bar visibility. * @param {number} [datasetIndex] - The dataset index * @param {string} [name] - The stack name to find * @param {number} [dataIndex] * @returns {number} The stack index * @private

(datasetIndex, name, dataIndex)

	 * @private
	 */
  _getStackIndex(datasetIndex, name, dataIndex) {
    const stacks = this._getStacks(datasetIndex, dataIndex);
    const index = (name !== undefined)
      ? stacks.indexOf(name)
      : -1; // indexOf returns -1 if element is not present

    return (index === -1)
      ? stacks.length - 1
      : index;
  }

  /**
	 * @private