refactor template-level subs pattern

packages/telescope-posts/lib/client/templates/posts_list/posts_list_controller.js

@@ -2,89 +2,54 @@
 
 /*
 
-This template acts as the controller that sets and manages the reactive context 
-for the embedded postsList template. It receives its parameters from a "caller" template.
+This template acts as the controller that sets and manages the reactive data context 
+for the embedded postsList template. 
+
+It doesn't care if it receives its context from the router or from another template. 
 
 */
 
-
 Template.postsListController.onCreated(function () {
 
-  // 1. Initialization (*not* reactive!)
   var instance = this;
-  var terms = instance.data.terms; // provided by the caller template
 
+  // if a limit is provided by the data context use this, else use default
+  var limit = !!instance.data.terms.limit ? instance.data.terms.limit : Settings.get('postsPerPage', 10);
 
-  // if terms doesn't have a limit, set one
-  if (!terms.limit) {
-    terms.limit = Settings.get('postsPerPage', 10);
-  }
-
-  // initialize the reactive variables
-  instance.postsLoaded = new ReactiveVar(0);
-  instance.terms = new ReactiveVar(terms);
-
-  // 2. Autorun
-
-  // will re-run when terms are changed, either by the router or by the template itself
-  instance.autorun(function () {
-
-    // console.log('// ⚡ autorun ------------------------');
-
-    // ⚡ reactive variables ⚡
-    var routerTerms = Router.current().data().terms; // get terms from router (category, date, etc.)
-    var instanceTerms = instance.terms.get(); // get terms from instance (posts limit)
-
-    var terms = _.extend(instanceTerms, routerTerms); // merge both
-
-    var subsReady = instance.subscriptionsReady();
-
-    // console.log("> Asking for " + terms.limit + " posts…");
-
-    // subscribe
-    var postsSubscription = instance.subscribe('postsList', terms);
-    var usersSubscription = instance.subscribe('postsListUsers', terms);
-
-    // if subscriptions are ready, set limit to newLimit
-    if (subsReady) {
-
-      // console.log("> Received "+terms.limit+" posts.");
-      instance.postsLoaded.set(terms.limit);
-
-    } else {
-      // console.log("> Subscriptions are not ready yet.");
-    }
-  
-  });
-
-  // 3. Cursor
-
-  instance.getPostsCursor = function() {
-
-    // console.log('// cursor ----------')
-    // console.log('> actually loaded ' + instance.postsLoaded.get() + ' posts')
-
-    var termsGet = _.clone(instance.terms.get());
-    var termsLoaded = _.extend(termsGet, {limit: instance.postsLoaded.get()});
-    var parameters = Posts.getSubParams(termsLoaded);
-
-    return Posts.find(parameters.find, parameters.options);
-  };
+  // initialize postsLimit template instance reactive variable
+  instance.postsLimit = new ReactiveVar(limit);
 
 });
 
 Template.postsListController.helpers({
   context: function () {
 
-    // console.log('// context ---------')
-    
-    // create context for postsList module
     var instance = Template.instance();
 
-    // ⚡ reactive variables ⚡
-    var terms = instance.terms.get();
-    var postsCursor = instance.getPostsCursor();
-    var postsReady = instance.subscriptionsReady();
+    // get terms from data context
+    var terms = this.terms; // ⚡ reactive ⚡
+
+    // get limit from template instance reactive variable
+    var postsLimit = instance.postsLimit.get(); // ⚡ reactive ⚡
+
+    // use limit to get subscriptions terms, then subscribe
+    var subscriptionTerms = _.extend(_.clone(terms), {limit: postsLimit}); // extend terms with limit
+    var postsSubscription = instance.subscribe('postsList', subscriptionTerms);
+    var usersSubscription = instance.subscribe('postsListUsers', subscriptionTerms);
+    var subscriptionsReady = instance.subscriptionsReady(); // ⚡ reactive ⚡
+
+    // if subscriptions are ready, update query terms to match the ones we subscribed with
+    if (subscriptionsReady) {
+      terms = subscriptionTerms;
+    }
+
+    // console.log('// ------ context running ------ //');
+    // console.log("terms: ", terms);
+    // console.log("limit: ", postsLimit);
+    // console.log("ready: ", subscriptionsReady);
+
+    var parameters = Posts.getSubParams(terms);
+    var postsCursor = Posts.find(parameters.find, parameters.options);
 
     var context = {
 
@@ -92,19 +57,19 @@ Template.postsListController.helpers({
       postsCursor: postsCursor,
 
       // posts subscription readiness, used to show spinner
-      postsReady: postsReady,
+      postsReady: subscriptionsReady,
 
       // whether to show the load more button or not
-      hasMorePosts: postsCursor.count() >= terms.limit,
+      hasMorePosts: postsCursor.count() >= postsLimit,
 
       // what to do when user clicks "load more"
       loadMoreHandler: function (instance) {
         event.preventDefault();
-
-        // increase limit by 5 and update terms
-        terms.limit += Settings.get('postsPerPage', 10);
-        instance.terms.set(terms);
-
+        var limit = instance.postsLimit.get();
+        // increase limit by 5 and update instance variable
+        limit += Settings.get('postsPerPage', 10);
+        instance.postsLimit.set(limit);
+        //TODO: also update URL
       },
 
       // the current instance