11-notifications.md.erb

---
title: Notifications
slug: notifications
date: 0011/01/01
number: 11
contents: Add a notifications collection to notify users of other user's actions.|Learn how to only share the relevant notifications with a given user.|Learn more about Meteor publications and subscriptions.
paragraphs: 30
---

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### Creating Notifications

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- ////
- ////
- ////

~~~js
Notifications = new Mongo.Collection('notifications');

Notifications.allow({
  update: function(userId, doc, fieldNames) {
    return ownsDocument(userId, doc) && 
      fieldNames.length === 1 && fieldNames[0] === 'read';
  }
});

createCommentNotification = function(comment) {
  var post = Posts.findOne(comment.postId);
  if (comment.userId !== post.userId) {
    Notifications.insert({
      userId: post.userId,
      postId: post._id,
      commentId: comment._id,
      commenterName: comment.author,
      read: false
    });
  }
};
~~~
<%= caption "lib/collections/notifications.js" %>

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~~~js
Comments = new Mongo.Collection('comments');

Meteor.methods({
  commentInsert: function(commentAttributes) {

    //...
    
    comment = _.extend(commentAttributes, {
      userId: user._id,
      author: user.username,
      submitted: new Date()
    });
    
    // update the post with the number of comments
    Posts.update(comment.postId, {$inc: {commentsCount: 1}});

    // create the comment, save the id
    comment._id = Comments.insert(comment);
    
    // now create a notification, informing the user that there's been a comment
    createCommentNotification(comment);
    
    return comment._id;
  }
});
~~~
<%= caption "lib/collections/comments.js" %>
<%= highlight "17~123" %>

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~~~js
Meteor.publish('posts', function() {
  return Posts.find();
});

Meteor.publish('comments', function(postId) {
  check(postId, String);
  return Comments.find({postId: postId});
});

Meteor.publish('notifications', function() {
  return Notifications.find();
});
~~~
<%= caption "server/publications.js" %>
<%= highlight "10~12" %>

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~~~js
Router.configure({
  layoutTemplate: 'layout',
  loadingTemplate: 'loading',
  notFoundTemplate: 'notFound',
  waitOn: function() {
    return [Meteor.subscribe('posts'), Meteor.subscribe('notifications')]
  }
});
~~~
<%= caption "lib/router.js" %>
<%= highlight "6" %>

<%= commit "11-1", "Added basic notifications collection." %>

### Displaying Notifications

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~~~html
<template name="header">
  <nav class="navbar navbar-default" role="navigation">
    <div class="container-fluid">
      <div class="navbar-header">
        <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#navigation">
          <span class="sr-only">Toggle navigation</span>
          <span class="icon-bar"></span>
          <span class="icon-bar"></span>
          <span class="icon-bar"></span>
        </button>
        <a class="navbar-brand" href="{{pathFor 'postsList'}}">Microscope</a>
      </div>
      <div class="collapse navbar-collapse" id="navigation">
        <ul class="nav navbar-nav">
          {{#if currentUser}}
            <li>
              <a href="{{pathFor 'postSubmit'}}">Submit Post</a>
            </li>
            <li class="dropdown">
              {{> notifications}}
            </li>
          {{/if}}
        </ul>
        <ul class="nav navbar-nav navbar-right">
          {{> loginButtons}}
        </ul>
      </div>
    </div>
  </nav>
</template>
~~~
<%= caption "client/templates/includes/header.html" %>
<%= highlight "15~22" %>

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~~~html
<template name="notifications">
  <a href="#" class="dropdown-toggle" data-toggle="dropdown">
    Notifications
    {{#if notificationCount}}
      <span class="badge badge-inverse">{{notificationCount}}</span>
    {{/if}}
    <b class="caret"></b>
  </a>
  <ul class="notification dropdown-menu">
    {{#if notificationCount}}
      {{#each notifications}}
        {{> notificationItem}}
      {{/each}}
    {{else}}
      <li><span>No Notifications</span></li>
    {{/if}}
  </ul>
</template>

<template name="notificationItem">
  <li>
    <a href="{{notificationPostPath}}">
      <strong>{{commenterName}}</strong> commented on your post
    </a>
  </li>
</template>
~~~
<%= caption "client/templates/notifications/notifications.html" %>

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~~~js
Template.notifications.helpers({
  notifications: function() {
    return Notifications.find({userId: Meteor.userId(), read: false});
  },
  notificationCount: function(){
  	return Notifications.find({userId: Meteor.userId(), read: false}).count();
  }
});

Template.notificationItem.helpers({
  notificationPostPath: function() {
    return Router.routes.postPage.path({_id: this.postId});
  }
});

Template.notificationItem.events({
  'click a': function() {
    Notifications.update(this._id, {$set: {read: true}});
  }
});
~~~
<%= caption "client/templates/notifications/notifications.js" %>

<%= commit "11-2", "Display notifications in the header." %>

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<%= screenshot "11-1", "Displaying notifications." %>

### Controlling access to notifications

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~~~js
❯ Notifications.find().count();
1
~~~
<%= caption "Browser console" %>

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~~~js
Meteor.publish('notifications', function() {
  return Notifications.find({userId: this.userId, read: false});
});
~~~
<%= caption "server/publications.js" %>

<%= commit "11-3", "Only sync notifications that are relevant to the user." %>

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~~~js
❯ Notifications.find().count();
1
~~~
<%= caption "Browser console (user 1)" %>

~~~js
❯ Notifications.find().count();
0
~~~
<%= caption "Browser console (user 2)" %>

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