Download CSV file on client side

i have written a API to export User collection to CSV , from MONGODB . the API is called on a button click and it export the data into CSV ... now the problem is that when this API is called it generates the RESULT FILE IN MY PROJECT , i want the result file to get Download on client side , means when user click on EXPORT button it show a SAVE AS option , USER select the fOLDER , NAME etc and then the file get downloaded on CLIENT COMPUTER ... any idea how to acheive this ... I,M using NODE JS , MONGODB and JSON2CSV module for data conversion ... below is my code

app.get('/USER/exporttocsv', function (req, res, next) {
    USER.find().select('-__v').lean().exec({}, function (err, products) {
        const json2csvParser = new Json2csvParser({ header: true });
        const csvData = json2csvParser.parse(products);
        fs.writeFile("bezkoder_mongodb_fs.csv", csvData, function (error) {
            if (error) throw error;
            console.log("Write to bezkoder_mongodb_fs.csv successfully!");
        });
    });
})