Vendor/phpspreadsheet/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Worksheet/Worksheet.php
public function duplicateStyle(Style $pCellStyle, $pRange)
    {
        // Add the style to the workbook if necessary
        $workbook = $this->parent;
        if ($existingStyle = $this->parent->getCellXfByHashCode($pCellStyle->getHashCode())) {
            // there is already such cell Xf in our collection
            $xfIndex = $existingStyle->getIndex();
        } else {
            // we don't have such a cell Xf, need to add
            $workbook->addCellXf($pCellStyle);
            $xfIndex = $pCellStyle->getIndex();
        }

        // Calculate range outer borders
        list($rangeStart, $rangeEnd) = Coordinate::rangeBoundaries($pRange . ':' . $pRange);

        // Make sure we can loop upwards on rows and columns
        if ($rangeStart[0] > $rangeEnd[0] && $rangeStart[1] > $rangeEnd[1]) {
            $tmp = $rangeStart;
            $rangeStart = $rangeEnd;
            $rangeEnd = $tmp;
        }

        // Loop through cells and apply styles
        for ($col = $rangeStart[0]; $col <= $rangeEnd[0]; ++$col) {
            for ($row = $rangeStart[1]; $row <= $rangeEnd[1]; ++$row) {
                $this->getCell(Coordinate::stringFromColumnIndex($col) . $row)->setXfIndex($xfIndex);
            }
        }

        return $this;
    }
public function duplicateStyle(Style $pCellStyle, $pRange)
    {
        // Add the style to the workbook if necessary
        $workbook = $this->parent;
        if ($existingStyle = $this->parent->getCellXfByHashCode($pCellStyle->getHashCode())) {
            // there is already such cell Xf in our collection
            $xfIndex = $existingStyle->getIndex();
        } else {
            // we don't have such a cell Xf, need to add
            $workbook->addCellXf($pCellStyle);
            $xfIndex = $pCellStyle->getIndex();
        }

        // Calculate range outer borders
        list($rangeStart, $rangeEnd) = Coordinate::rangeBoundaries($pRange . ':' . $pRange);

        // Make sure we can loop upwards on rows and columns
        if ($rangeStart[0] > $rangeEnd[0] && $rangeStart[1] > $rangeEnd[1]) {
            $tmp = $rangeStart;
            $rangeStart = $rangeEnd;
            $rangeEnd = $tmp;
        }

        // Loop through cells and apply styles
        for ($col = $rangeStart[0]; $col <= $rangeEnd[0]; ++$col) {
            for ($row = $rangeStart[1]; $row <= $rangeEnd[1]; ++$row) {
                $this->getCell(Coordinate::stringFromColumnIndex($col) . $row)->setXfIndex($xfIndex);
            }
        }

        return $this;
    }
Duplicate cell style to a range of cells.

Please note that this will overwrite existing cell styles for cells in range!

@param Style $pCellStyle Cell style to duplicate
@param string $pRange Range of cells (i.e. "A1:B10"), or just one cell (i.e. "A1")

@throws Exception

@return Worksheet