Submitting radio button using ajax and php into mysql database - php

Question

I am working with sweetalert2 two trying to submit form data including radio button. I find that the other fields are recorded in the database but can find the radio button values. Can somebody help? Check the code below.
This is the form
<form class="login" method="post" action="register.php">
<h5>Please Sign Up</h5>
<div class="form-group">
<input id="f_name" class="form-control" type="text" name="f_name" placeholder="Your First Name" required>
<input id="l_name" class="form-control" type="text" name="l_name" placeholder="Your Last Name" required>
<input id="email" class="form-control" type="email" name="email" placeholder="Your email address" required>
<input id="pass" class="form-control" type="password" name="pass" placeholder="Your password" required>
<h4>I want to :</h4>
<div class="radio-toolbar">
<input class="user" type="radio" name="user" id="user1" value="user1">
<label class="radio-label" for="writer">User 1</label>
<input type="radio" name="user" id="user2" value="user2">
<label class="radio-label" for="client">User 2</label>
</div>
<button class="btn btn-secondary" name="submit" id="register">Sign Up</button>
</div>
<h6><span>Have an account?</span> </h6>
Log In
</form>
External js is this
$(function() {
$('#register').click(function(e){
var valid = this.form.checkValidity();
if (valid) {
var f_name = $('#f_name').val();
var l_name = $('#l_name').val();
var email = $('#email').val();
var pass = $('#pass').val();
var user = $("input[name='user']:checked").val();
e.preventDefault();
$.ajax({
type: 'POST',
url: 'process.php',
data: {f_name:f_name,l_name:l_name,email:email,pass:pass, user:user},
success:function(data){
Swal.fire({
icon: 'succes',
title: 'Check the below message',
text: data,
footer: 'Please Sign In'
})
},
error:function(data){
Swal.fire({
icon: 'error',
title: 'Errors',
text: data,
footer: '<a href>Why do I have this issue?</a>'
})
}
});
}else{
}
});
});
The php code is here
require_once('./config/db.php');
if (isset($_POST)){
$f_name = $_POST['f_name'];
$l_name = $_POST['l_name'];
$email = $_POST['email'];
$pass = sha1($_POST['pass']);
$user = $_POST['user'];
$stmt = $conn->prepare("SELECT * FROM users WHERE email=?");
$stmt->execute([$email]);
$user = $stmt->fetch();
if ($user) {
echo "Email already exists in the database! Please use another email!";
} else {
$sql= "INSERT INTO users(f_name,l_name,email,pass,user) VALUES(?,?,?,?,?)";
$stmt = $conn->prepare($sql);
$results = $stmt->execute([$f_name,$l_name,$email,$pass,$user]);
if ($results) {
echo "Your registration has been submitted successfully.";
}else{
echo "There were errors while saving the data.";
}
}
}
?>
Please assist. I have been trying some of the solutions in the stackoverflow but can't get any help.