javascripters event sep 17, 2016 · 2:00 pm: scalable javascript design patterns

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JavaScriptersCommunity to Connect, Share & Explore

http://www.javascripters.org

Email: pune.javascripters@gmail.com

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About JavaScriptersJavaScripters is an initiative taken for front-end engineers community to share and gain JavaScript basic and advance knowledge along with moto to connect all javascripters together.

We conduct technical discussion forums, sessions, workshops, trainings and knowledge sharing meet-ups around the city, for all front-end / UI engineers on core & advance(object oriented) level javascript concepts, along with all latest javascript frameworks like AngularJS, NodeJs, emberJs, TypeScript, ReactJs technologies by experts.

• Since : April 2015

• Members : Around 2500+

• Speakers & Mentors : 17

• Events/ Meetup Conducted: 5

• Feature Planned Events : 10 events confirmed till December 2016

Our initiatives:

WhatsApp Group (2)Meetup Groups JavaScriptes PuneJs HTML5-Web-Mobile-Development-Meetup Pune-UX-UI-Engineers WebF

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List of upcoming events

1.JS Performance tips and tricks

2.BootStrap , CSS and Responsive Design

3.JavaScript Design Patterns

4.Introduction of Design thinking for front-end Engineers

5.React JS with Material design

6.Introduction to Angular 2.x

7.Practice with TypeSpcript

8.Introduction to ES6

9.Automated javascript workflow with Gulp

10.NodeJs practice session

11. Total (3) online webinar under planning

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Our Sponsor

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• Laxman M• Tushar Jadhav

About Speaker

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WHY ARE WE HERE ?

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What is Pattern?

A pattern is a reusable solution that can be applied to commonly occurring problems.

Another way of looking at pattern is as templates for how we solve problems.

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Anti-Patterns

Anti-patterns represents a lesson that has been learned.

• Describes a bad solution to a particular problem that resulted in bad situation occurring

• Describe how to get out of said situation and how to go from there to a good solution

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Benefits

• Patterns are proven solutions• Patterns can be easily reused• Patterns can be expressive

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What is “good” pattern?

A pattern is considered good if it• solves a particular problem• does not have an obvious solution• describes a proven concept• describes a relationship

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Categories of Design Patterns

• Creational Design Patternsfocus on object-creation mechanism

• Structural Design Patternsconcerned with object composition and relationship between objects

• Behavioural Design Patternsfocus on improving or streamlining the communication between disparate

objects

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Overview

• Constructor Pattern• Module Pattern• Singleton Pattern• Observer Pattern• Prototype Pattern• Facade Pattern• Factory Pattern• Decorator Pattern

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Constructor Pattern

A constructor is a special method used to initialise a newly created object once memory has been allocated for it.

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Module Pattern

Modules are an integral piece of any robust application’s architecture and typically help in keeping the units of code for a project both cleanly separated and organised.

Modules can be implemented using• Object literal notation• The Module pattern• AMD modules• CommonJS modules• ECMAScript Harmony modules

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The Module pattern

A way to provide both private and public encapsulation for classes.

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The Module pattern

Advantages:• Encapsulation• Privacy

Disadvantages:• Cannot access private members in the methods that are added to the object

at later point• Inability to create automated unit tests for private members

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Revealing Module Pattern

In Module pattern,1. repeat the name of module each time when accessing public

method/variable from other public method2. switch to object literal notation to make things public

The updated module pattern in which all the functions and variables are defined in private scope and return an anonymous object with pointers to the private members to reveal them publicly.

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Revealing Module Pattern

Advantages:• Readability

Disadvantages:• If a private function refers to public function, that public function can’t be

overridden• Public object members that refer to private variables are also subject to no-

patch rule

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Singleton Pattern

The singleton pattern restricts instantiation of a class to a single object.

Classically, the Singleton pattern can be implemented by creating a class with a method that creates a new instance of the class if one doesn’t exist.

In JavaScript, Singletons serve as a shared resource namespace which isolate implementation code from the global namespace so as to provide a single point of access for functions.

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Observer Pattern

In Observer pattern, an object(subject) maintains a list of objects depending on it(observers) automatically notifying them of any changes to state.

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Difference between Observer and Pub/Sub Pattern

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Observer and Pub/Sub Pattern

Advantages:• Loosely Coupled• Flexibility

Disadvantages:• In Pub/Sub, by decoupling publishers from subscribers, it can sometimes

become difficult to obtain guarantees that particular parts of the application are functioning as we may expect

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Prototype Pattern

Creates objects based on a template of an existing object through cloning.

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Facade Pattern

This pattern provides a convenient higher-level interface to a larger body of code, hiding its true underlying complexity.

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Facade Pattern

Advantages:• Simplicity• Abstraction

Disadvantages:• Performance

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Factory Pattern

A factory provides a generic interface for creating objects, where we can specify the type of factory object we wish to create.

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Decorator Pattern

Decorators are structural design pattern that aims to promote code reuse. They can be used to modify existing systems where we wish to add additional features to objects without the need to heavily modify the underlying code.

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Decorator Pattern

Advantages:• Flexible

Disadvantages:• If poorly managed, it can add complexity

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Can we check what we have learned ?

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Register for upcoming events

3.BootStrap , CSS and Responsive Design

4.Introduction of Design thinking for front-end Engineers

5.React JS with Material design

6.Introduction to Angular 2.x

7.Practice with TypeScript

8.Introduction to ES6

9.Automated javascript workflow with Gulp

10.NodeJs practice session

11. Total (3) online webinar under planning