Read large Excel(.xls or .xlsx) or CSV files with php libraries

I wrote a function which reads large Excel(.xls or .xlsx) or CSV files with php libraries. The function uses following libraries.

1. Procedure to install php libraries

1.1. Install Composer (a tool for dependency management in php)

$ mkdir composer
$ cd composer/
$ curl -sS https://getcomposer.org/installer | php
$ sudo mv composer.phar /usr/local/bin/composer
$ sudo chmod +x /usr/local/bin/composer

1.2. Install PhpSpreadsheet (a library for reading and writing spreadsheets such as xlsx, xls, ods and csv)

$ composer require phpoffice/phpspreadsheet

1.3. Install Spout (a library for reading and writing 3 types of spreadsheets xlsx, ods and csv)

$ composer require "box/spout"

2. A function which reads large Excel(.xls or .xlsx) or CSV files

The function below reads spreadsheet data from large Excel(.xls or .xlsx) or CSV files and store them in a 2 dimensional array. It takes following 2 arguments.

require_once('/path-to-composer/composer/vendor/autoload.php');

use PhpOffice\PhpSpreadsheet\Spreadsheet;
use PhpOffice\PhpSpreadsheet\Reader\Csv as CsvReader;
use PhpOffice\PhpSpreadsheet\Reader\Xls as XlsReader;
use PhpOffice\PhpSpreadsheet\Reader\Xlsx as XlsxReader;

use Box\Spout\Reader\Common\Creator\ReaderEntityFactory as SpoutReaderEntityFactory;

function getExcelSheetData($targetFileName, $fileType) {

    $sheetData = "";

    if ($fileType == "csv" || $fileType == "xls") {
        $sheetData = getExcelSheetDataWithPhpSpreadsheet($targetFileName, $fileType);
    } else if ($fileType == "xlsx") {
        $sheetData = getExcelSheetDataWithSpout($targetFileName, $fileType);
    } else {
        // Error Handling
    }

    return $sheetData;
}


function getExcelSheetDataWithPhpSpreadsheet($targetFileName, $fileType) {

    $reader = null;

    if ($fileType == "csv") {
        $reader = new CsvReader();
    } else if ($fileType == "xls") {
        $reader = new XlsReader();
    } else {
        // Error Handling
    }

    $reader->setReadDataOnly(TRUE);

    try {
        $spreadSheet = $reader->load($targetFileName);
    } catch (Error | Exception $ex) {
        // Error Handling
    }

    // get data from active sheet
    $sheet = $spreadSheet->getActiveSheet();

    $row = 1;
    foreach ($sheet->getRowIterator() as $eachRow) {
        foreach($sheet->getColumnIterator() as $column) {
            $sheetData[$row - 1][]
                = $sheet->getCell($column->getColumnIndex() . $row)->getValue();
        }
        $row++;
    }

    $spreadSheet->disconnectWorksheets();
    return $sheetData;
}


function getExcelSheetDataWithSpout($targetFileName, $fileType) {

    if ($fileType != "xlsx") {
        // Error Handling
    }

    $reader = SpoutReaderEntityFactory::createXLSXReader();

    try {
        $reader->open($targetFileName);
    } catch (Error | Exception $ex) {
        // Error Handling
    }

    // read data from "active" sheet
    foreach ($reader->getSheetIterator() as $sheet) {
        if ($sheet->isActive()) {
            $row = 1;
            foreach ($sheet->getRowIterator() as $eachRow) {
                $column = 1;
                foreach ($eachRow->getCells() as $cell) {
                    $sheetData[$row - 1][] = $cell->getValue();
                    $column++;
                }
                $row++;
            }
            break; // no need to read more sheets
        }
    }

    $reader->close();
    return $sheetData;
}