meteor/docs/client/basic/sections/session.md

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Session

Session provides a global object on the client that you can use to store an arbitrary set of key-value pairs. Use it to store things like the currently selected item in a list.

What's special about Session is that it's reactive. If you call Session.get("myKey") in a template helper or inside Tracker.autorun, the relevant part of the template will automatically be re-rendered whenever Session.set("myKey", newValue) is called.

{{> autoApiBox "Session.set"}}

{{> autoApiBox "Session.get"}}

Example:

<!-- In your template -->
<template name="main">
  <p>We've always been at war with {{dstache}}theEnemy}}.</p>
</template>

// In your JavaScript
Template.main.helpers({
  theEnemy: function () {
    return Session.get("enemy");
  }
});

Session.set("enemy", "Eastasia");
// Page will say "We've always been at war with Eastasia"

Session.set("enemy", "Eurasia");
// Page will change to say "We've always been at war with Eurasia"

Using Session gives us our first taste of "reactivity", the idea that the view should update automatically when necessary, without us having to call a "render" function manually. In the next section, we will learn how to use Tracker, the lightweight library that makes this possible in Meteor.

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