--- /dev/null
+import _ from 'lodash';
+import calculateCellHeight from './calculateCellHeight';
+
+/**
+ * Calculates the vertical row span index.
+ *
+ * @param {Array[]} rows
+ * @param {Object} config
+ * @returns {number[]}
+ */
+export default (rows, config) => {
+ const tableWidth = rows[0].length;
+
+ const rowSpanIndex = [];
+
+ rows.forEach((cells) => {
+ const cellHeightIndex = new Array(tableWidth).fill(1);
+
+ cells.forEach((value, index1) => {
+ if (!_.isNumber(config.columns[index1].width)) {
+ throw new TypeError('column[index].width must be a number.');
+ }
+
+ if (!_.isBoolean(config.columns[index1].wrapWord)) {
+ throw new TypeError('column[index].wrapWord must be a boolean.');
+ }
+
+ cellHeightIndex[index1] = calculateCellHeight(value, config.columns[index1].width, config.columns[index1].wrapWord);
+ });
+
+ rowSpanIndex.push(_.max(cellHeightIndex));
+ });
+
+ return rowSpanIndex;
+};