Meteor - Tracker


Tracker is a small library used for auto updating templates once the Session variable has changed. In this chapter, we will learn how the tracker works.

First, we will create a button that will be used for updating the session.


      {{> myTemplate}}
<template name = "myTemplate">
   <button id = "myButton">CLICK ME</button>

Next, we will set the starting session value myData and create a mySession object. Tracker.autorun method is used for keeping an eye on mySession. Whenever this object changes, the template will auto-update. To test it, we will set a click event for updating.


if (Meteor.isClient) {
   var myData = 0
   Session.set('mySession', myData);

   Tracker.autorun(function () {
      var sessionData = Session.get('mySession');

      'click #myButton': function() {
         Session.set('mySession', myData ++);

If we click the CLICK ME button five times, we will see that the tracker is logging new values every time the session updates.

Meteor Tracker Log