pubSubJS.js

document.addEventListener("DOMContentLoaded", function(event) {
  var orderModule = (function() {
    var orders = {},
      EST_DELIVERY = "current estimated delivery time",
      estimatedDeliveryTime;

    PubSub.subscribe(EST_DELIVERY, function(msg, data) {
      console.log(msg);
      estimatedDeliveryTime = data;
    });

    return orders;
  })();

  var deliveryModule = (function() {
    var deliveries = {},
      EST_DELIVERY = "current estimated delivery time";

    deliveries.getEstimatedDeliveryTime = function() {
      var estimatedDeliveryTime = 1; // Hard-coded to 1 hour, but likely an API call.

      PubSub.publish(EST_DELIVERY, estimatedDeliveryTime);
    };

    return deliveries;
  })();

  deliveryModule.getEstimatedDeliveryTime();
});