(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, MacOS

var os = require('os');
if (os.platform() == 'win32') {  
  var chilkat = require('@chilkat/ck-node23-win64'); 
} else if (os.platform() == 'linux') {
    if (os.arch() == 'arm') {
        var chilkat = require('@chilkat/ck-node23-linux-arm');
    } else if (os.arch() == 'arm64') {
        var chilkat = require('@chilkat/ck-node23-linux-arm64');
    } else {
        var chilkat = require('@chilkat/ck-node23-linux-x64');
    }
} else if (os.platform() == 'darwin') {
  var chilkat = require('@chilkat/ck-node23-darwin-universal');
}

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();