New revolutionary framework

  • First of its kind
  • Beautifully written
  • Extensively Documented
  • Super Easy to learn

Why use Meteor?

Realtime Apps

  • Update all connected clients effortlessly
  • Realtime by default

Rapid Prototyping

  • Roll out your MVP when everyone is setting their build systems
  • All you need is meteor
  • Compatible with variety of 3rd party JS libraries

Fast Iteration

  • Flexibility to do things your way
  • Create modular apps with packages
  • Make rapid iteration your second nature

Highly opinionated

  • All your js and CSS is minified and concatenated 
  • All templates are compiled to JS and minified and concatenated with rest of JS
  • All JS files are wrapped in IEFs
  • Globals for exports

Yet very flexible

  • Modular to its core
  • Based on simple but powerful principles

What makes Meteor so special?

Realtime Apps by default

FullStack Framework

All you need is Meteor

if (Meteor.isClient) {
    console.log("Logging on Client");
}

if (Meteor.isServer) {
    console.log("Logging on Server");
}

if (Meteor.isCordova) {
    console.log("Logging on Phonegap");
}

Database Everywhere

Todos = new Mongo.Collection('todos');  // runs on both client and server

if (Meteor.isServer) {
    //runs only on server
    Meteor.startup(function() {
        Todos.insert({body: 'Very important thing to do', done: false});
    });
}

if (Meteor.isClient) {
    //runs only on client
    var todos = Todos.find({done: false}).forEach(function(todo) {
        Todos.update({_id: todo._id}, {$set: {done: true} });
    });

Reactive

&

 Declarative

Escape from Callback Hell

Out of the box compatibility with 3rd party JS

 

  • npm
  • bower
  • Jquery Plugins
  • d3
  • svg

Packages

  • Core to write modular code
  • Provide a way around almost all meteor's opinions
  • Easy to write and test
Package.describe({
  summary: "My awesome package or a sub app, or whatever",
  version: "0.0.1",
  name: "username:package",
  git: 'https://github.com/username/package'
});

Tutorial:

Simple Notice Board App

Finished Product

  • Allow user login with email/password
  • Create and delete notices
  • Likes for Notices
  • Realtime - All clients see new updates immediately
  • An iOS app 

App Structure

client  - Loaded on client only

client/compatibility  - Isn't wrapped in IEFs

server - Loaded on server only

lib  -  Loaded first in directory

public  -  For static assets on client

private  -  For static assets on server

tests  -  For tests, not loaded anywhere

 

Code Load Order

  • Code in deepest directory
  • Code in 'lib' directory
  • Code sorted by filename
  • Code with name matching 'main.*'

Blaze

  • Client side champ
  • Responsible for reactively change Templates
  • Independent of Templating Engine used

Spacebars

  • Default templating engine of meteor
  • "Inspired" by handlebars
  • Flexible and brain dead simple
<template name="noticeList">
  <ul>
    {{#each notices}}
    <li>
      <span class="notice">{{body}}</span>
      <span class="delete"><i class="glyphicon glyphicon-trash"></i></span>
      <span class="like ">
        <i class="glyphicon glyphicon-heart"></i>
        <span class="like-count">{{likeCount}}</span>
      </span>
    </li>
    {{/each}}

  </ul>

</template>

Interaction with Templates

Helpers - Template data providers, arbitrary methods etc

Events - Well, event handlers

Template.noticeList.helpers({
  notices: function() {
    return Notices.find({}, {sort: {like_count: -1}});
  }
});
Template.noticeList.events({
  "click .like": function(e) {
    Notices.update(this._id, {$inc: {like_count: 1}});
  },
  "click .delete": function(e) {
    Notices.remove(this._id);
  }
});

Database Connectivity

Create Collection

Use it

Notices = new Mongo.Collection('notices');

Notices.find({}, {sort: {like_count: -1}});

Notices.insert({
        body: e.currentTarget.value,
        like_count: 0
});

Notices.update("some_id", {$inc: {like_count: 1}});

Notices.remove("some_id");

Database Security

Allow / Deny callbacks for Collections

  • All the changes to data (from client) pass through deny and allow callbacks (in that order)
  • If any deny callback returns true, or any allow callback returns false, the change is prohibited
Notices.allow({
  insert: function(userId, doc) {
    return true;
  },
  update: function(userId, doc) {
    return true;
  },
  remove: function(userId, doc) {
    return true;
  }
});

Database Control

Control what and how much goes to Clients

Publishers / Subscribers

  • Publish the data you want for the users you want
  • Publishes Live Queries : The data on client updates when it changes on server
Meteor.publish('all_notices', function() {
  return Notices.find();
});

Template.noticeList.created = function() {
  Meteor.subscribe('all_notices');
};

Authentication

  • Official packages for adding authentication with various mediums
  • Add auth with email, Facebook, Twitter etc with minimal effort
//SIGN UP
Accounts.createUser({
  email: email,
  password: password
}, function(err) {
  if (err) {
    console.log("Creating user", err);
  }
});
//LOG IN
Meteor.loginWithPassword(
  email,
  password,
  function(err) {
    if (err) {
      console.log("Login:", err);
    }
  })

Mobile Apps

  • Create a basic cordova app with one command
  • Easily add cordova plugins
  • Use same codebase across various platforms
$ meteor add-platform ios
$ meteor build ios

Digging a Little Deeper

DDP

  • Distributed Data Protocol 
  • Really simple protocol to allow talking over sockets consistent
  • It just defines names for messages sent over sockets
  • Allows writing your own client or server (or both) for meteor

Alternative Metor Clients

Say Thank You DDP!

Android

iOS

Xamarin

Javascript

Others

https://github.com/delight-im/Android-DDP

http://fastchicken.co.nz/2014/02/11/making-xamarin-ios-talk-to-meteor/

https://github.com/boundsj/ObjectiveDDP

https://github.com/mondora/asteroid

http://meteorpedia.com/read/DDP_Clients

Tracker

Man behind reactivity

  • Weighs about 1 KB
  • Say hello to TRP (Transparent Reactive Programming) in Javascript
  • Allows interaction between reactive data providers and consumers with no boilerplate
  • e.g interaction between the data from the database and HTML templates in Meteor

Live Query

  • Make a query for some data, and get the updates whenever that data changes
  • At present only support Mongodb for production use

Fibers

Synchronous (like) Development for Nodejs

  • Non blocking Synchronous Javascript on Server
  • Actually, asynchronous code but without callbacks
  • Completely abstracted by Meteor's APIs
  • Don't worry, we can still use async code with little to no extra work

Some Common Pitfalls

Load order

Or lack of control over it

  • Unconfigurable load order
  • Rename or put files in sub-dirs to control their load order

 

No fixed Structure for Code

  • Not enough opinion in this regard
  • server, client, lib are decided, but what goes inside them is upto the dev
  • Provides flexibility, but have seen people doing abusing this

Namespacing

  • Everything (global) in App namespace
  • Globals in a file are exported to app namespace
  • Can cause confusion combined with lack of control on load order

Globals revived

Getting over

Pitfalls

Use packages

  • Divide app into modular packages
  • Use umbrella packages for dependency management
  • Allow control over code load order, exports, and easy testing

Create a Global Namespace

Use models

  • Use meteor's `transform` to create classes for your data
  • Put reusable code with the data
  • Keep the code DRY

Make use of Code Sharing

  • Use common code for validation on both client and server
  • Create structural units for your code
  • e.g share validation code 
  • Can keep them as static functions with your models

Thank You

Happy Hacking with Meteor :)

@bitspook

Meteor.js @ Jschannel Feb 2015

By Charanjit Singh

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Meteor.js @ Jschannel Feb 2015

Meteor js presentation at jschannel Feb 2015 meetup

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