Suggest User name based on full name and date of birth - html

Question

HTML -
<form action="/addUser" method="post">
<div class="Fields hideme">
<label class="form__fields">Full Name :<span class="star"> * </span></label>
<input class="input" type="text" name="full_name" placeholder="Enter your name" required><br/>
</div>
<div class="Fields hideme">
<label class="form__fields">Address line 1:<span class="star"> * </span></label>
<input class="input" type="text" name="address_line_1" placeholder="Address line 1" required><br/>
</div>
<div class="Fields hideme">
<label class="form__fields">DOB :<span class="star"> * </span></label>
<input class="input" type="date" name="DOB" placeholder="DOB" required><br/>
</div>
</div>
<div class="Fields hideme">
<label class="form__fields">Email :<span class="star"> * </span></label>
<input class="input" type="email" name="email" placeholder="Enter your E-mail" required><br/>
</div>
<div class="Fields hideme">
<input class="Submit_button" type="submit" value="Submit">
</div>
</form>
I am saving this user using node.js
JS -
var nameSchema = new mongoose.Schema({
full_Name: String,
.
.
email: String
});
var User = mongoose.model("User", nameSchema);
const publicPath = path.join(__dirname,'/');
app.use(express.static(publicPath));
app.post("/addUser", (req, res) => {
var myData = new User(req.body);
myData.save()
.then(item => {
res.send("User saved to database");
})
.catch(err => {
res.status(400).send("Unable to save to database");
});
});
I have a html form in which I am asking a user to enter info like Name, DOB, address, Email and I have to suggest User Names based on these inputs to the user.
Please tell me how to send back a suggested userName based on the inputs by the user(full name, DOB, address).

Answer 1

I wanted to write in the comments but I don't have enough reputations.
So I will write it as an answer.
I personally recommend you to use heroku or digitalocean because they are very good for nodejs.
mlab is the best for your DB if you are using MongoDB.
And you can google it or search on youtube there are tons of information.
I hope you will find the answer.