Vulcan/packages/example-customization/lib/callbacks.js

/*
Let's add a callback to the new post method that
appends a random emoji to the newly submitted post's title.
*/

import { addCallback } from 'meteor/vulcan:core';

function PostsNewAddRandomEmoji (post, user) {

  post.title = post.title + " " +_.sample(["🎉", "💎", "☠", "⏱", "🎈", "⛱"])

  return post;
}
addCallback("posts.new.sync", PostsNewAddRandomEmoji);