Author: Roopesh Chinnakampalli

Developer. Blogger. Technology Evangelist. Community Contributor.

React is FAST in what sense?

Today I was debating with my colleague on how React is fast and in what sense? It was interesting discussion and we thought of exploring on this context, hence blogging it for my reference!

I assume, you’ve knowledge on React JS framework before reading this article!

React is FAST in the sense of DOM updates!!!

How React is fast in updating the DOM (Document Object Model) ?

  1. React creates Virtual DOM (React builds and maintains an internal representation of the rendered UI. It includes the React elements you return from your components. This representation lets React avoid creating DOM nodes and accessing existing ones beyond necessity, as that can be slower than operations on JavaScript objects. Sometimes it is referred to as a “virtual DOM”) for every component.
  2. Tracks for the changes happening in the react component and updates the Virtual DOM.
  3. Reconciliation happens with the actual DOM for the changes in the Virtual DOM.

It’s all the React magic of transforming the model changes to views!

I’ve come across few blogs posts where they explained the inner details of the React JS and Virtual DOM. Here are few of them –

Real Benefits of React JS Virtual DOM

React: The Virtual DOM

VideoTech Talk : How React.js works

Happy Programming!

Web Tool – Create React App

Facebook has come up with one of the best JavaScript frameworks to build fast & scalable web apps. In this fast paced web development world, with countless dependencies, build frameworks & utility libraries, we may be spending time in choosing the right one’s get started.

May be Facebook would thought through this and they came up with a tool – create-react-app. This tools allows to create react app within no time.

I personally tried this tool for getting started with creating a HelloWorld react app and I did it in few mins!

create-react-app is a CLI which helps scaffolds all the required libraries and build frameworks and help us to focus on building the app without worrying on the setting up the project!

Here is the cool user guide on how to use this tool!

Happy Programming!

Hybrid Apps – Android System WebView Updates

From Android Lollipop 5.0, Google started pushing an app called “Android System Web View”, which they periodically update the device web view. Since Apache Cordova / Adobe PhoneGap is well adopted for building cross platform Mobile apps, this will have significant impact on the apps we’ve already built!

If you’re a Hybrid app developer and supporting Android 5.0 Lollipop & above versions, it’s worth to keep an eye on these updates and test your apps often.

It’s highly recommended to subscribe Chrome Canary beta channel – Android System WebView beta to get the updates early and act accordingly.

You can join Google+ WebView beta community to get latest updates. Android System WebView is supported on Android Lollipop 5.0 & above versions.

How to uninstall the Web View update

  • Tap on the Settings icon.

  • Scroll down and tap on Apps or Application Manager.

  • Look for Android System WebView under Downloaded page.

  • Tap to open the info page.

  • Now click on UNINSTALL UPDATES button. This will reset the web view.

NOTE: It’s a temporary solution till you work out a fix for it. If any of your existing app is breaking in the production, you can quickly ask them to uninstall the Android System WebView update.

Hope it helps!

Get started with Web

Web is very powerful. It’s almost replaced the desktop environment. Here are the few resources to get started –

  1. Codecademy
  2. CodeSchool
  3. Google Web
  4. Mozilla Developer Network
  5. Microsoft Virtual Academy  – Lot of cool video courses available for FREE!
    1. Getting Started with Web Technologies
    2. The Modern Web Platform Jump Start

  6. Udacity Courses ( FREE )

 

Happy learning!!!

Bower – A Package Manager

Recently I blogged on Modern Web App development, in which I mentioned few tools which will ease the web development. Today, let’s explore one more tool – Bower, the package manager for Web.

As you may aware that modern web application development requires one to many libraries or frameworks, and maintaining all of them is really hard, especially while upgrading! Isn’t cool, if we have a tool to do this job! Let’s take a look at the tool –

Bower is a great tool which helps us to maintain the project or app dependencies in more elegant way!

How it works?

Bower uses bower.json manifest (similar to package.json) file to hold all the package information. You can easily edit this manifest file. Works like a configuration file for your packages. Using Bower commands you can install all those packages at once.

Installing Bower

You can install Bower using npm (Node Package Manager). If you don’t know what is npm, you can learn here – https://docs.npmjs.com/. So, if you don’t have npm installed on your machine. Install the Node.js, which will install Node as well as npm.

NOTE: Bower requires Git. So install Git before you proceed with Bower installation.

  1. Node.js 
  2. Git

You may have to open Terminal(on MAC OS) or PowerShell / Command Prompt (on Windows). [I recommend PowerShell on Windows than Command Prompt.]

Type the following command –

npm install -g bower

NOTE: You may get permission issues, so you run the above command using sudo in MAC. On Windows, run the PowerShell or Command Prompt with Administrator Privileges.

Once you are done installing Bower globally, now we are ready to play with it!

Now, we need to create bower.json manifest file. You can create this manifest file manually or through bower.

Manually creating bower.json – Create a file and rename it to bower.json. That’s it! Data included in this manifest file should adhere to the spec –  https://github.com/bower/bower.json-spec

A Sample bower.json for Angular app

{
 "name": "demo-app",
 "version": "1.0.0",
 "dependencies": {
 "angular": "^1.3.0",
  "bootstrap": "^3.2.0",
 "angular-animate": "^1.3.0",
 "angular-cookies": "^1.3.0",
 "angular-resource": "^1.3.0",
 "angular-route": "^1.3.0",
 "angular-sanitize": "^1.3.0",
 "angular-touch": "^1.3.0"
 },
 "devDependencies": {
 "angular-mocks": "~1.3.0",
 "angular-scenario": "~1.3.0"
 },
 
}

Interactively create bower.json – You can create the bower.json interactively using  –

bower init

Answer the questions popped by Bower and it will create the file for you.

How to add new packages?

Try the following command –

//install the package and add it to bower.json dependencies
bower install <package-name> --save
//Ex: bower install jquery --save

You can search for available packages  – http://bower.io/search/

Update the bower package  –

bower update <package-name> <package-name> [options]

//-F: Force latest version on conflict

//Ex: bower update jquery -F

Uninstall the bower package  –

bower uninstall <package-name> [options]

//-S: Remove uninstalled packages from the project’s bower.json dependencies

//Ex: bower uninstall jquery -S

More Bower API’s – http://bower.io/docs/api/

Can I register my own package or library?

Yep, you can do that using bower register – 

bower register <your-package-name> <git-endpoint>

//Ex: bower register mylibrary git://github.com/user/example.git

You can also unregister – http://bower.io/docs/creating-packages/#unregister

Bower comes with lot of tools, which allows you to integrate the Bower with other IDE’s and tools. More info – http://bower.io/docs/tools/

Hope you have got quick overview of Bower package manager and usage of the tool.

Happy Web Programming!

Quick look of Keyboard events on Mobile browsers

As part of the project, we were working on the forcing the user to enter correct information while keying in. We tried leveraging the keyCode, charCode & which properties on event object.

We did a quick trial by creating a demo Hybrid App and tested the same on the Android and iOS devices. The results were surprising!

Google Chrome to be the future rich browser which is FAILING and Apple’s Mobile Safari is WINNING. Google Chrome browser is failing to return the correct key codes from Android OS KitKat 4.4 and above.

So, it’s better to have the validation check while submitting the form instead of keying in!

I have created a demo page to test the same – KeyEvents

Below are the quick analysis on different Android and iOS devices –

Device & OS Status
Samsung Galaxy NOTE 8000 (4.1.2)      √
Samsung Galaxy S3 (4.3)      √
Samsung Galaxy S4 (4.4.2)      ×
Nexus 7 (4.4.4)      ×
Nexus 7 (5.1)      ×
Nexus 9 (5.1)      ×
Nexus 4 (5.1)      ×
Nexus 5 (5.1)      ×
Nexus 6 (5.0)      ×
Apple iPhone 6 Plus (8.0.2)      √
Apple iPhone 6 (8.1)      √
Apple iPhone 5S (8.0.2)      √
Apple iPhone 5 (7.1.2)      √
Apple iPhone 4S (8.0.2)      √
Apple iPad mini (8.0.2)      √
Apple iPad (6.1.3)      √
Apple iPad Air (7.1.1)      √

Happy Mobile programming!

Overview of Modern Web App Development

I started developing websites from the days, where JavaScript is considered as BAD and should be as minimal as possible – preferably for input validations. But things got changed over the time and JavaScript became the key for Web Apps!

I wish to share my encounter! Let’s start.

It was those days where Web App development is ruled by Server Side technologies like Classic ASP, ASP.NET, PHP etc., and JavaScript is used to do input validations. No AJAX. I have witnessed waiting for the site / app to load by looking at the blue progress bar in Internet Explorer (IE was dominant browser at that time).

Later AJAX introduced by Google through GMail app (though Microsoft IE has already have it through XmlHttpRequest ), which is revolutionary and it changes the way we develop apps. Developers considered AJAX as a powerful tool which can do miracles and it worked!

JavaScript started playing the key role in high performance web apps, where it triggered for Single Page ApplicationsSimultaneously developers started facing cross browser issues and it was really hard to achieve cross browser compatability! Hope you all agree with me.

Big thanks to John Resig for introducing jQuery library targeting cross browser issues which helped a lot! I know YUI(not actively maintained now) library already exists, but jQuery is instant hit and developers started using it and it’s open source!

With introduction of iPhone & Android, Mobile browsers started dominating desktop browser and they are powerful. This triggered injecting responsiveness to web apps through CSS3 Media Queries!

JavaScript started ruling the client side development and it’s time to take the JavaScript to Server Side. Ryan Dahl did it and called it as Node.jsIt again changed how we write server side code. May be if you wish to check first presentation on Node.js by Ryan himself!

Now developers started created packages of their libraries and pushing to npm (node package manager). Simultaneously CSS got better with frameworks like LESS and SASS.

Twitter created Bootstrap, a CSS framework which allowed to develop web app that are responsive targeting Mobile, Tablet and Desktop browsers! Also, they created bower, another package manager which is alternative to npm. Pros and cons of npm and bower is out of scope of this post!

SPA‘s got lot of attention and everyone started considering it instead of regular Multi page applications. It triggered to create MV* frameworks like Backbone JS, Angular JS etc.,

We have task runners – Grunt JS, Gulp JS to automate the tasks which we do repeatedly while building the app!

Frameworks changed the way we develop apps! Few of them :-

DOM Manipulation libraries:

jQuery, Lo-Dash, Underscore JS

HTML Templates:

Mustache JS, Handlebars JS

JavaScript MV* Frameworks:

Backbone JS, Knockout JS, Angular JS, Ember JS, React JS

Package Manager:

npm bower

Build Tools – TaskRunner:

GruntJSGulpJS

Scaffolding Tool:

Yeoman

Unit Test Framework:

QUnit, Jasmine, Karma

At Last, there are few developers, authors who guide & inspire us. Here are the few of them  –

Douglas Crockford, Paul Irish, Addy Osmani, Christian Heilmann, Remy Sharp, John Papa, Jake Archibald, Nicolas C Zakas, Yahuda Katz.

I strongly feel Web Apps will override Desktop apps. I will try my best to accomplish it!

Happy Web App programming!