Function groupBy

packages/table-core/src/utils/getGroupedRowModel.ts:177–190

(rows: Row<TData>[], columnId: string)

}

function groupBy<TData extends RowData>(rows: Row<TData>[], columnId: string) {
  const groupMap = new Map<any, Row<TData>[]>()

  return rows.reduce((map, row) => {
    const resKey = `${row.getGroupingValue(columnId)}`
    const previous = map.get(resKey)
    if (!previous) {
      map.set(resKey, [row])
    } else {
      previous.push(row)
    }
    return map
  }, groupMap)
}