So, I am creating a basic system which runs a login system in nodejs and express using an Excel file as a base. The excel CSV file will have a list of username and passwords and I am reading it using fast-csv. But when it is authenticating with the listing, it is matching only the first record. Not the other records in the excel. Any clue why? Code is as below:
index.js file
var express = require('express');
var path = require('path');
var app = express();
var bodyParser = require('body-parser');
var csv = require('fast-csv')
var fs = require('fs')
app.listen(80, function(){
    console.log("Server is running")
})
app.use(express.static(path.join(__dirname, 'public')));
app.use(bodyParser.urlencoded({extended : true}));
app.post("/", function (req,res) {
    fs.createReadStream(path.resolve(__dirname, 'master_data.csv'))
    .pipe(csv.parse({ headers: true}))
    .on('error', error => console.error(error))
    .on('data', row => {
        if(req.body.username == row.username && req.body.password === row.password && row.loggedIn == 'FALSE'){
            res.send("Login Successful. <br> Your link is available below:" + row.link)
        }else{
            res.send("Login Failed")
        }
    })
    // Log file created below
    var userSchema = {
        Username: req.body.username,
        loginDateTime: new Date().toString(),
        ipAddress: req.ip,
    };
    fs.appendFile('logfile.txt', JSON.stringify(userSchema) + ",", function(err, file){
        if(err) throw (err);
    })
});
index.html file
<html>
    <head>
        <title>School Login Page</title>
        <link rel="stylesheet" type="text/css" href="./css/mainCSS.css">
    </head>
    <body>
        <h2>School Login Page</h2><br>
        <p>Please enter all details exactly as per details provided to you.</p>
        <form action="/" method="POST">
            <label for="username">Username</label>
            <input type="text" id="username" name="username" value="" required><br><br>
            <label for="password">Password</label>
            <input type="password" id="password" name="password" required><br><br>
            <input type="submit" value="submit" id="submitButton">
        </form>
    </body>
</html>
I also want to create an alert for a failed login but I know that you cannot create alerts server side in nodejs. How can I do this is in the front-end? Thanks