(Node.js) Fetch 1st N Headers of Search Results

Calls Search to get a message set, then downloads the 1st N messages in the message set. There are two equivalent ways of doing it: (1) iterate from 0 to N-1 and download each message individually, or (2) create a new message set that contains the 1st N messages and pass it to FetchHeaders. Both are demonstrated here.

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 assumes 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 == false) {
        console.log(imap.LastErrorText);
        return;
    }

    var numFound = messageSet.Count;
    if (numFound == 0) {
        console.log("No messages found.");

        return;
    }

    // Get the 1st 10 messages in messageSet.
    var upperBound = 10;
    if (numFound < upperBound) {
        upperBound = numFound;
    }

    var i = 0;
    var bUid = messageSet.HasUids;
    while (i < upperBound) {

        // email: Email
        var email = imap.FetchSingleHeader(messageSet.GetId(i),bUid);
        if (imap.LastMethodSuccess == false) {
            console.log(imap.LastErrorText);

            return;

        }
        else {
            // Do whatever is needed with the email.. 
            // ....

        }

        i = i+1;
    }

    // Alternatively, create a new message set containing the 1st 10 message id's (UID's) 
    // from the search results message set:
    var firstTen = new chilkat.MessageSet();

    for (i = 0; i <= upperBound - 1; i++) {
        firstTen.InsertId(messageSet.GetId(i));
    }

    // Download the 1st ten headers:
    // bundle: EmailBundle
    var bundle;
    bundle = imap.FetchHeaders(firstTen);
    if (imap.LastMethodSuccess == false) {

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

    // Other examples show how to iterate over the emails contained within the bundle...

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


}

chilkatExample();