(Node.js) Read IMAP Email Headers

Call FetchHeaders to download only the email headers.

Install Chilkat for Node.js and Electron using npm at Chilkat npm packages for Node.js Chilkat npm packages for Electron on Windows, Linux, MacOSX, and ARM

var os = require('os');
if (os.platform() == 'win32') {  
    if (os.arch() == 'ia32') {
        var chilkat = require('@chilkat/ck-node21-win-ia32');
    } else {
        var chilkat = require('@chilkat/ck-node21-win64'); 
    }
} else if (os.platform() == 'linux') {
    if (os.arch() == 'arm') {
        var chilkat = require('@chilkat/ck-node21-arm');
    } else if (os.arch() == 'x86') {
        var chilkat = require('@chilkat/ck-node21-linux32');
    } else {
        var chilkat = require('@chilkat/ck-node21-linux64');
    }
} else if (os.platform() == 'darwin') {
    if (os.arch() == 'arm64') {
        var chilkat = require('@chilkat/ck-node21-mac-m1');
    } else {
        var chilkat = require('@chilkat/ck-node21-macosx');
    }
}

function chilkatExample() {

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

    var imap = new chilkat.Imap();

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

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

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

    // messageSet: MessageSet
    var messageSet;
    // We can choose to fetch UIDs or sequence numbers.
    var fetchUids = true;
    // Get the message IDs of all the emails in the mailbox
    messageSet = imap.Search("ALL",fetchUids);
    if (imap.LastMethodSuccess !== true) {
        console.log(imap.LastErrorText);
        return;
    }

    // When downloading headers, each email object contains
    // (obviously) the headers, but the body will be missing.
    // Also, attachments will not be included.  However, it is
    // possible to get information about the attachments
    // as well as the complete size of the email.
    // bundle: EmailBundle
    var bundle;
    bundle = imap.FetchHeaders(messageSet);
    if (imap.LastMethodSuccess !== true) {

        console.log(imap.LastErrorText);
        return;
    }

    // Loop over the email objects and display information
    // about each:
    var i;
    for (i = 0; i <= bundle.MessageCount - 1; i++) {
        // email: Email
        var email;
        email = bundle.GetEmail(i);

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

        // Display the recipients:
        var j;
        var name;
        var addr;
        for (j = 0; j <= email.NumTo - 1; j++) {
            name = email.GetToName(j);
            addr = email.GetToAddr(j);
            console.log(name + ", " + addr);
        }

        for (j = 0; j <= email.NumCC - 1; j++) {
            name = email.GetCcName(j);
            addr = email.GetCcAddr(j);
            console.log(name + ", " + addr);
        }

        // 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);
        for (j = 0; j <= numAttach - 1; j++) {
            console.log(imap.GetMailAttachFilename(email,j));
            var attachSize = imap.GetMailAttachSize(email,j);
            console.log("    size = " + attachSize + " bytes");
        }

        console.log("--");

    }

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


}

chilkatExample();