Converting XLSX to CSV on the server in Node not working

Question

I was trying to convert files from XLSX to CSV on the server, but when I make a post request on Postman, I get "Error importing users".

I am using this package to convert XLSX to CSV: https://www.npmjs.com/package/xlsx.

I tried the solution from: Convert XLS to CSV on the server in Node

Below is the function to import the file:

exports.importFromCSV = async function importFromCSV(req, res) {
    try {
        if (!req.user || !req.user.isRoot) throw new Error('Allowed only for Admin');
        if (!req.file) throw new Error('No file supplied');

        const csvString = await new Promise((resolve, reject) => {
                                        
            const workBook = XLSX.readFile(csvRows);
            XLSX.writeFile(workBook, userdata, { bookType: "csv" })
            fs.readFile(req.file.path, {encoding: 'utf-8'}, (err, data) => {
                if (err) return reject(err);
                resolve(data.toString());
            });
        });

        const csvRows = await promisify(csvParse)(csvString, {columns: true});
        const rows = csvRows.map(row => {
            const name = (row.name || '').split(/\s+/)[0].trim();
            const lastname = (row.lastname || '').trim();
            const username = `${_.snakeCase(name)}_${_.snakeCase(lastname)}`;
            const password = (row.password || '').trim();

            const invalid = [name, lastname, password, username].filter(e => !e).length;  
            return {
                value: row,
                user: new User({
                    name,
                    lastname,
                    username,
                    password,
                    groups: [],
                    favoriteFiles: [],
                    payingStatus: false,
                    isRoot: false
                }),
                invalid,

            };

        });

Does anyone have any idea what is wrong with the code? Thanks in advance!