Please the issue is that any emoji or special character are not rendering on the subject header of the pug file. but working perfectly on the body. I compile both body and subject header differently using pug.

const compileHtmlFunction = pug.compileFile(
    path.join(__dirname, "../emails", templatePath, "html.pug")
  );



const getSubjectFunction = pug.compileFile(
    path.join(__dirname, "../emails", templatePath, "subject.pug")
  );

const payload = {


  DestinationEmail: to,
    SourceEmail: fromEmail ? `Switch By Sterling ${fromEmail}` : "Switch By Sterling team@switch-ng.com",
    Body: compileHtmlFunction(data),
    Subject: getSubjectFunction(data)
  };

"""""""""""""""""""""""""""""""html.pug

doctype html
include ../../layouts/header

div(style='display: none; max-height: 0; overflow: hidden;')
div(style='background-color: #ecedfa; line-height: 30px; padding-top:5px;')
  div(style='background-color: #ffffff; color: #484347;  margin: 0 auto; margin-top: 100px; max-width: 400px; padding: 20px;')
    div 
      center 
        img(src='https://res.cloudinary.com/dzkyrqr5e/image/upload/v1648553921/new-headers/password-reset_ait4kd.png' alt='' width='100%' height="100%" border='0' style='display: block; margin: 20px auto 20px auto;')
    p(style='margin: 0 0 5px 0;')
      | Hello #{first_name},
      br
      | You are receiving this email because there has been a password change request on your account.
      | If you initiated this request, please change your password by clicking the 'Change my password' button below. The link will expire after 10 minutes.
      br
      a(href=updatePasswordUrl) Change my password
      br
      | If you didn't request this, please ignore this email. Your password won't change until you access the link above and create a new one.
      br
      p(style='margin: 0') With 💜
      | Your friends at Switch

    include ../../layouts/footer_image

""""""""""""""""""""""""""""subject.pug

| Launch  💜