Sample code for 30+ languages & platforms
JavaScript

Imap.GetMailSize vs Email.Size

Shows how to get the total size of an email, as well as the sizes of the attachments. This can be done when either full-emails or headers-only are downloaded.
Note
This example is intended for running within a Chilkat.Js embedded JavaScript engine. All Chilkat JavaScript examples require Chilkat v11.4.0 or greater.
JavaScript
var success = false;

// This example assumes the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

var imap = new CkImap();

// Connect to an IMAP server.
// Use TLS
imap.Ssl = true;
imap.Port = 993;
success = imap.Connect("imap.example.com");
if (success == false) {
    console.log(imap.LastErrorText);
    return;
}

// Login
success = imap.Login("****","****");
if (success == false) {
    console.log(imap.LastErrorText);
    return;
}

// Select an IMAP mailbox
success = imap.SelectMailbox("Inbox");
if (success == false) {
    console.log(imap.LastErrorText);
    return;
}

// Get the message IDs of all the emails in the mailbox
// We can choose to fetch UIDs or sequence numbers.
var fetchUids = true;
var messageSet = new CkMessageSet();
success = imap.QueryMbx("ALL",fetchUids,messageSet);
if (success == false) {
    console.log(imap.LastErrorText);
    return;
}

// When downloading headers, each email object contains
// (obviously) the headers, but the body will be missing.
// Attachments will not be included.  However, it is
// possible to get information about the attachments
// as well as the complete size of the email.
var bundle = new CkEmailBundle();
var headersOnly = true;
success = imap.FetchMsgSet(headersOnly,messageSet,bundle);
if (success == false) {
    console.log(imap.LastErrorText);
    return;
}

// Loop over the email objects and display information about each:
var email = new CkEmail();
var i = 0;
var j = 0;
var numEmails = bundle.MessageCount;
while (i < numEmails) {
    bundle.EmailAt(i,email);

    // Display the From and Subject
    console.log(email.From);
    console.log(email.Subject);

    // Display the recipients:
    j = 0;
    while (j < email.NumTo) {
        console.log("TO: " + email.GetToName(j) + ", " + email.GetToAddr(j));
        j = j+1;
    }

    j = 0;
    while (j < email.NumCC) {
        console.log("CC: " + email.GetCcName(j) + ", " + email.GetCcAddr(j));
        j = j+1;
    }

    // Show the total size of the email, including body and attachments:
    console.log(email.Size);

    // When a full email is downloaded, we would use the
    // email.NumAttachments property in conjunction with the
    // email.GetMailAttach* methods.
    // However, when an email object contains only the header,
    // we need to access the attachment info differently:
    var numAttach = imap.GetMailNumAttach(email);
    j = 0;
    while (j < numAttach) {
        console.log(imap.GetMailAttachFilename(email,j));
        var attachSize = imap.GetMailAttachSize(email,j);
        console.log("    size = " + attachSize + " bytes");
        j = j+1;
    }

    console.log("--");

    i = i+1;
}

// Disconnect from the IMAP server.
success = imap.Disconnect();