Making a template helper reactive in Meteor

Question

I am building a chat application and on my \"new chats\" page I have a list of contacts, which you can select one by one by tapping them (upon which I apply a CSS selected class

Answer 1

1) Define Tracker.Dependency in the same place where you define your object:

var newChatters = [];
var newChattersDep = new Tracker.Dependency();

2) Use depend() before you read from the object:

Template.newChatDetails.newChatters = function() {
  newChattersDep.depend();
  return newChatters;
};

3) Use changed() after you write:

Template.contactsLayout.events({
  'click #contactItem': function(e, t) {
    ...
    newChatters.push(...);
    newChattersDep.changed();
  },
});