Vendor/phpspreadsheet/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Writer/Xlsx/Style.php
public function allBorders(Spreadsheet $spreadsheet)
    {
        // Get an array of unique borders
        $aBorders = [];
        $aStyles = $this->allStyles($spreadsheet);

        /** @var \PhpOffice\PhpSpreadsheet\Style\Style $style */
        foreach ($aStyles as $style) {
            if (!isset($aBorders[$style->getBorders()->getHashCode()])) {
                $aBorders[$style->getBorders()->getHashCode()] = $style->getBorders();
            }
        }

        return $aBorders;
    }
public function allBorders(Spreadsheet $spreadsheet)
    {
        // Get an array of unique borders
        $aBorders = [];
        $aStyles = $this->allStyles($spreadsheet);

        /** @var \PhpOffice\PhpSpreadsheet\Style\Style $style */
        foreach ($aStyles as $style) {
            if (!isset($aBorders[$style->getBorders()->getHashCode()])) {
                $aBorders[$style->getBorders()->getHashCode()] = $style->getBorders();
            }
        }

        return $aBorders;
    }
Get an array of all borders.

@param Spreadsheet $spreadsheet

@return Borders[] All borders in PhpSpreadsheet