How to send files through SMTPJS?

  email, file, html, javascript, smtp

I have the following HTML code:

<form method = "POST" name = "submissionsFrom">
            Full Name:
            <input type = "text" name = "subject" value = "" id = "name">
            <textarea name = "message" id = "message"></textarea> 
            Select file:
            <input type = "file" accept = ".docx" required id = "file" name = "file"> 

         <input type="button" value="Send Email" onclick="sendEmail()"/>

And this is the JavaScript (using SMTP):

        let name = document.forms["submissionsFrom"]["name"].value;
        var message = document.forms["submissionsFrom"]["message"].value;
        var file = document.forms["submissionsFrom"]["file"];
        function sendEmail() {
        message = document.getElementById("message").value;

        Host: "",
        Username : "[email protected]",
        Password : "passwordHere",
        To : '[email protected]',
        From : "[email protected]",
        Subject : "Email Submission",
        Body : message,
        Attachments : [
            // name : "",
            // path: 

            message => alert("Submission sent!")

What I want is, instead of a file already assigned with the attachments array, I’d like for the user to attach a file and send it in the email along with the body text that they put in.
I already have the rest working, but I’m struggling with figuring out how to make the user upload a file that’ll be sent in the email.

Source: Ask Javascript Questions