React Native

Attach a File with an Explicit Content Type

Demonstrates the Chilkat Email.AddFileAttachment2 method, which attaches a file from the filesystem and lets you explicitly specify its content type rather than having Chilkat infer it from the file extension. This example attaches a binary file as application/octet-stream.

Background: Extension-based type detection is convenient but not always right — a file may have an unusual or missing extension, or you may need a very specific MIME type for the recipient to process it correctly. Specifying the content type explicitly removes the guesswork. application/octet-stream is the generic "arbitrary binary data" type, a safe default that tells the client to treat the attachment as an opaque download rather than trying to render it.

Chilkat React Native Downloads

Download Chilkat for React Native

React Native

import { Email } from '@chilkat/react-native'

function chilkatExample() {
  // Demonstrates the AddFileAttachment2 method, which attaches a file and lets you
  // explicitly specify its content type instead of letting Chilkat infer it.

  const email = new Email();
  email.subject = 'Email with a file attachment';
  email.body = 'Please see the attached file.';

  // Attach a file, explicitly specifying the content type.
  try {
    email.addFileAttachment2('qa_data/attachments/data.bin', 'application/octet-stream');
  } catch {
    console.log(email.lastErrorText);
    return;
  }

  console.log(`NumAttachments = ${email.numAttachments}`);

  // Note: The path "qa_data/attachments/data.bin" is a relative local filesystem path,
  // relative to the current working directory of the running application.
}