(Node.js) Add Header Field to MIME Sub-Header in Email

Demonstrates how to add a header field to one of the attachment sub-headers in an email.

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 email = new chilkat.Email();

    email.Subject = "test";
    email.AddTo("Chilkat","support@chilkatsoft.com");
    email.From = "Matt <matt@example.com>";
    email.Body = "This is a simple plain-text body.";

    var success = email.AddFileAttachment2("qa_data/1.HPM","application/x-hprimnet");
    if (success !== true) {
        console.log(email.LastErrorText);
        return;
    }

    // Add a "ContentDescription: HPM/3.0" in the attachment's sub-header.
    // The 1st attachment is at index 0.
    email.AddAttachmentHeader(0,"Content-Description","HPM/3.0");

    // Show the email MIME:
    console.log(email.GetMime());

    // This is the output:
    // (Note: When Chilkat sends email, all CKX-* headers are removed prior to sending.)

    // MIME-Version: 1.0
    // Date: Wed, 16 Jan 2019 10:05:18 -0600
    // Message-ID: <93B88835586270B7BE5202F84E171F29C10BA935@CHILKATSLICE>
    // Content-Type: multipart/mixed; boundary="------------000502000000020502010608"
    // X-Priority: 3 (Normal)
    // Subject: test
    // To: Chilkat <support@chilkatsoft.com>
    // From: Matt <matt@example.com>
    // CKX-Bounce-Address: matt@example.com
    // 
    // --------------000502000000020502010608
    // Content-Type: text/plain; charset=us-ascii; format=flowed
    // Content-Transfer-Encoding: 7bit
    // 
    // This is a simple plain-text body.
    // --------------000502000000020502010608
    // Content-Type: application/x-hprimnet; name="1.HPM"
    // Content-Transfer-Encoding: base64
    // Content-Disposition: attachment; filename="1.HPM"
    // Content-Description: HPM/3.0
    // 
    // FILE_DATA_IS_HERE...
    // 
    // --------------000502000000020502010608--

}

chilkatExample();