Mandrill API with Handlebars "each-loop" not working - go

Question

Met problem when using Mandrill API to send transactional newsletters. I chose Handlebars for the template parameters. The user name was shown correctly, but data in the list (post titles) were empty. Please help indicate if anything I did wrong. Thank you!
The template is as below, sent to the endpoint /messages/send.json :
func genHTMLTemplate() string {
return "code generated template<br>" +
"Hi {{name}}, <br>" +
"{{#each posts}}<div>" +
"TITLE {{title}}, THIS {{this}}<br>" +
"</div>{{/each}}"
}
The API log in my Settings panel in mandrillapp.com shows the parameters:
{
"key": "xxxxxxxxxx",
"message": {
:
"merge_language": "handlebars",
"global_merge_vars": null,
"merge_vars": [
{
"rcpt": "xxxxxx#gmail.com",
"vars": [
{
"name": "posts",
"content": [
{
"title": "title A"
},
{
"title": "title B"
},
]
},
{
"name": "name",
"content": "John Doe"
}
]
}
],
:
},
:
}
And below is the email received. "title A" and "title B" are expected after "TITLE".
code generated template
Hi John Doe,
TITLE, THIS Array
TITLE, THIS Array

Answer 1

Mandrill decided to create custom handlebars helpers with some horrible, HORRIBLE names:
https://mandrill.zendesk.com/hc/en-us/articles/205582537-Using-Handlebars-for-Dynamic-Content#inline-helpers-available-in-mandrill
title and url will definitely give you grief if your objects happen to have keys named title and urlas well. Why they didn't name their helpers something like toTitleCase and encodeUrl is beyond me.
As far as arrays and #each is concerned, you can work around it by using {{this.title}} instead of {{title}}.

Answer 2

After testing with Mandrill's sample code here I found the key "title" just doesn't work. Dunno the reason (a reserved keyword of Mandrill?) but replace it with "title1", "titleX" or something else it can be rendered correctly.
{
"name": "posts",
"content": [
{
"title": "blah blah" // "title1" or something else works
},
}

Answer 3

while using handlebars as the merge language 'title' is the reserved helpername which is used in handlebars which makes your text in title case. If you do only {{title}} by default it considers as title the empty text. try giving it {{title title}} which should work or changing the key name to something else ( if you dont want your title in title case )

Answer 4

I know this is late but it could be of use to someone trying to debug this issue currently. Take note of this point in the Mandrill documentation
There are two main ways to add dynamic content via merge tags: Handlebars or the Mailchimp merge language. You may already be familiar with the Mailchimp merge language from creating and editing Mailchimp templates. We also offer a custom implementation of Handlebars, which is open source and offers greater flexibility.
To set your merge language, navigate to Sending Defaults and select Mailchimp or Handlebars from the Merge Language drop-down menu.
I've run into a similar issue on Sending Blue, where their default configuration does not enable handle bars so it won't evaluate them.