角流星收集onchange

Question

I have 2 mongo meteor collections, named applications and sliders I have a service that subscribes to them and when they are ready, it populates an array in tree format.

the problem is that when the collection changes nothing is telling the service about it. So if I print the collections and the array into html, the first time everything is synced, but after a change to the collection only the collection changes.. not the array

in short, when the collection in the db changes the meteor collection is updated, but not my "section" array

in my service:

var applications, sliders;
var sections = [{
              name: 'Getting Started',
              //state: 'home.gettingstarted',
              type: 'link'
            }];



          $meteor.subscribe('applications').then(function(subscriptionHandle) {
            applications = $meteor.collection(Applications);
          }).then(function(subscriptionHandle) {
            $meteor.subscribe('sliders').then(function(subscriptionHandle) {
              sliders = $meteor.collection(Sliders);
              createSections();
            });
          });


function createSections() {
//some login to create a tree
            for (var i = 0; i < applications.length; i++) {
              var pages = [];
              for (var j = 0; j < sliders.length; j++) {
                if (sliders[j].appId != applications[i].id())
                  continue;
                var page = {};
                page.name = sliders[j].nm;
                page.type = "link";
                page.data = sliders[j];
                pages.push(page);
              }
              sections.push({
                name: applications[i].nm,
                type: 'toggle',
                pages: pages,
                data: applications[i]
              });
            }
          }

the controller in using the service. the html is looping the sections.

Answer 1

You're calling createSections in the subscription callback, which will only fire one time upon subscription .ready() . It sounds like instead you wish to update sections each time the applications collection is modified. In that case, you could use applications. observeChanges which will fire each time documents are added, changed, or removed from your collection. Something like:

applications.observeChanges({
  added: function(id, doc) {
    // do stuff with added documents
  }
});

Don't forget that Minimongo cursors are by default reactive, so long as you call them in a reactive data context so a simple applications.find().forEach(function(doc){}) could be enough for your purposes.