Mailchimp/Mandrill and Handlebars changing preview text - handlebars.js

Question

I'm working with MailChimps Mandrill to send transnational emails with handlebars. The whole setup is done and the emails send absolutely fine - but when they arrive they still have the default Mailchimp template string for the preview text that look like:
|*MC_PREVIEW*|
Is anyone aware of a way to remove this from showing or change it? Currently I have to go into the code of the email in Mandrill and remove the block of code myself - wondering if there is a way to do that from Mailchimps end at all as it's a bit tedious every time an email template is updated and exported back to Mandrill to go in and remove it again.
Thanks in advance!

Answer 1

I've had this issue, and what helped me was first changing the Mandrill default merge tags to Handlebars, then re-exporting the templates from Mailchimp back to Mandrill.
This converts all *|Mailchimp|* style merge tags in the code of the email into {{handlebars}}-style.
Important Edit:
If your Mailchimp templates are using handlebars to define the merge tags, these will get escaped like so:
\{{mergeTag}}
You will either have to manually delete these backslashes to get the tags to work again, OR reformat the merge tags in Mailchimp to be in the *|MAILCHIMP|* style before exporting.
If you choose the latter, when converting a camelCase merge tag to Mailchimp style, just put it in all caps.
E.g. {{mergeTag}} becomes *|MERGETAG|*

Answer 2

We encountered the same issue and wrote a little lambda http endoint that we can trigger via slack integration to fix all our mandrill templates:
const mailchimpFactory = require('#mailchimp/mailchimp_transactional');
const mailchimp = mailchimpFactory(process.env.MAILCHIMP_API_KEY);
function fixTemplate({ name, code }) {
const regex = /\*\|MC_PREVIEW_TEXT\|\*/ig; // regexr.com/69390
const fixedBody = code.replace(regex, '');
console.log(`Updating ${name}`);
return mailchimp.templates.update({
name,
code: fixedBody,
});
}
// removes all mailchimp preview merge variables from all
// templates in mandrill (since we're using handlebars)
async function fixAllTemplates(event) {
const templates = await mailchimp.templates.list();
await Promise.all(templates.map(fixTemplate));
const templateList = templates.map(({ name }) => `\n> ${name}`).join('');
const msg = `*Mandrill Template Fixer:* Updated ${templates.length} templates. ${templateList}`;
console.log(msg);
return { statusCode: 200, body: msg };
}
module.exports = { fixAllTemplates };