Getting PostId for a comment using Autoform for Meteor

Without an auto-form, we usually do below to submit a comment:

comment-submit.js

 'submit form': function(e, template) {
     e.preventDefault();

     var $body = $(e.target).find('[name=body]');
     var status = {
       body: $body.val(),
       postId: template.data._id
     };

      

        
        
        
      

    

We can inject a postId into each comment.

How can I do this with Autoform?

I tried this alongside the collection of comments:

 Comments = new Mongo.Collection('comments');

 Comments.before.insert(function (userId, doc) {
   doc.postId = Posts.findOne()._id; 
 });



 Comments.attachSchema(new SimpleSchema({
   body: {
     type: String,
     autoform: {
       'label-type': 'placeholder',
       placeholder: 'Add your comment…'
     }
   },
   postId: {
     type: String
   }
 }));

      

        
        
        
      

    

It works, but it always gets the postId of the 1st post in the collection, even it's actually the 2nd, 3rd, or other than the 1st post.

Please guide. Thank.