Call inside Iron Router hook


I have a subscription inside my waitOn router hook, that takes a date as an argument:

waitOn: function() {
  var t =;
  var period = moment(t).subtract(1, 'days').valueOf();
  return Meteor.subscribe('posts', period);

the problem is, calling makes the hook rerun infinitely.

I tried using _.once from the underscore library:

var t = _.once(function () { return; });

but I can’t get it to work. It does not return the date.