Get ReactiveVar in anonymous function

Question

I am using meteor reactive-var package. How can i get reactive variable in a anonymous function that is defined in templates's js file? viewer.js:

Template.viewer.helpers({
    counter: function () {
        return Template.instance().counter.get();
    }
});

Template.viewer.onCreated(function() {
    this.counter =  new ReactiveVar(0);
});

Template.viewer.onRendered(function(e){
    viewerRendered();
});

function getCounter() {
    // !!Return reactive counter variable
}

function viewerRendered() {
    var counter = getCounter();
    $(document).trigger("ViewerCreated",counter);
}

Thanks.

Answer 1

If you need to access the current template in an external function through the onRendered() callback, you have multiple ways:

1. Using the external function as a direct callback :

   Template.viewer.onRendered(viewerRendered)
   
   function viewerRendered() {
     let currentTemplate = this
     //...
   }
   

2. Passing the current template as parameter :

   Template.viewer.onRendered(function() {
     viewerRendered(this)
   })
   
   function viewerRendered(currentTemplate) {
     //...
   

JavaScript functions are quite flexible since this is dynamic, there is other ways to access the data.
The two above are simple use-cases.

You may do whatever you want with the template such as accessing its data, using subscriptions...