This JS library is created by a software engineer named Jorden Walke who was working in Facebook (may be still working I don’t know) and since then it is being maintained by the Facebook itself. It was first deployed for Facebook News feed around 2011. Later on in 2013 React was open sourced at JS conference. An open source project is where the code to a certain project is completely open that means like anybody can readily see the code that went into a project. Open source project are community based and accept help from other programmers globally as a part of contribution.

One of the basic doubt often students face about its naming notations like React.js , React or something like ReactJS → so all these naming notations can be used; different websites use different notations.
React creates a Virtual Dom in computer memory which is why we don’t need internet connection once it gets loaded to the browser. React knows only one thing that is to create an awesome UI.

About React

React follows the component based approach. A component is one of the core building blocks of react. We can say that every application we are going to develop in React will be made up of pieces called components. Components make the task of building UIs much easier and reduce the repetition of code.
React uses a declarative approach means react only changes what it needs to be changed (i.e., suppose you went into a hotel and ask for some food later on you are served with food, now you don’t care how the food was prepared likewise the declarative process works ).
React is designed for speed, simplicity and scalability.

How to Use

To use and learn React, one should set up a React Environment on computer. It uses create-react-app tool which is an officially supported way to create React application.
Node.js (node-modules) is also required to use the react application so make sure you have installed node.js !

→Open Visual studio code
→Click on terminal
→Click on new terminal
→You will see a pop up to the bottom of window !
→ Run the command npx create-react-app app-name !
note that npx always uses the latest version of create-react-app
→ Wait for some time (it may take more time depending on the strength of your PC or Computer).

After it installed you will see something like this

Now run the command cd app-name in order to change the directory and then again run another command npm start and press ENTER to see the magic in your default browser.

→Open your folder by selecting your project name ( app-name )

→ Go to app.js file of src folder and start coding in react

PROGRAMMING IS A GAME, PLAY IT ON YOUR OWN WAY !

AJIT SHARMA

When I started to learn bootstrap it was an amazing experience, I don’t think every commercial websites are possible without using bootstrap.

Bootstrap is an amazing HTML, CSS, and Java-Script framework which helps in responsive, mobile type projects on web.

Why to use Bootstrap ?

Since it is launched in August 2011, bootstrap has attend a lot of light. Bootstrap has become the developer’s choice for UI development. And there are so many reason which gives it a boost.

A developer’s choice: → Unlike most of the framework available in the market, bootstrap is one of the simplest to implement and use in the market; its implementation is as simple as importing CSS and using the classes available.

Device friendly : Bootstrap responsiveness makes it all much simple ! it can intelligently “sense” the device’s resolution and screen width an adjust the content accordingly.

Customisable : Bootstrap is easily customisable. Before downloading the version from the site, you can set your own custom fonts, sizes, colour schemes and everything.

Huge community: Bootstrap is supported by the huge open source community present on Git-hub. Any bugs and issues are resolved in no time for the release !

Development friendly : With almost all the common features that is to require in web applications or websites pre-built, it makes the developers

job much easier and reduces the time required for development.

JavaScript aided : Bootstrap comes in with a pre-built JS file that adds a lot of functioning features to support its elements.

Well documented : he official bootstrap site offers inn detail documentation of all the elements and features provided by it. It’s easy to understand and offers in-depth explanations.

Grid system : → Bootstrap uses a 12-columns grid system that is responsive. It also offers offset feature and nested screen sizes in mind or can be just simply used to structure your content efficiency.

All these are just a few points that makes bootstrap popular. There are many more which we get know on our own as we make ourselves familiar with it.

THANK YOU !

by AJIT SHARMA

This is having a mass meaning (GLOBE) but I am going to share the changes I faced around my village circle. Skipping the first five years(was so sensitive to remember the things). It was year 2006 when I came to know that actually there is a long time database running in the world, and it has twelve columns like something called months. But the life has to go on anyway. It was spring, I was sitting in between the mango trees(tree garden) with many homo sapiens. Some of them were discussing about years, politics, do’s and don’t.

At evening I came to my legend mother; in a fancy way (in my local language )

I uttered “weather is very clear, that slowing and fastening wind is really effective”, she laughed a little and said to me “this is not going to be permanent” I didn’t get her, but her meaning was “time changes”.

Everything was developing and growing with me. In 2007 I remember there was an election, it was some crowdy atmosphere aside my house(near gov. school) → I hate politics !

So, as it is true -> “time changes” and it changed the whole HTML (structure) of my village. Changes in surroundings, changes in that greenery atmosphere, changes in people’s mentality as well; they started occupying unowned land, started to fight each other.

What hurts me a lot; they shared that greenery mango trees among them(disjoint-families) and had cut their own part trees, either they sold it or had eaten but left that space for being deserted (still uncovered). Also they made two parties in village and they fought brutally at least twice in a year.

It is goodness of the village that after eight years they realized, they have something to loose.

I mentioned the title as GLOBE because I think such type of incidents are being happened approx in every village of INDIA especially that conspiring politics.

May be these things were as usual before I landed but its all about the changes a kid faced, losing the expectations of that atmospheric affection.

Everyone is selfish now, eagerly they are applying for the form of jealousy.

An author ZIG ZIGLAR said “A clear rejection is better than a fake promise”.

But a person drowning in the sea of selfishness, can’t get its meaning →never.

These were the things I wanna share in life, I am done with it today.

There are mores to write upon.

THANKS FOR READING !

by AJIT SHARMA

You might have heard about compiler, may be unfamiliar to transpiler: let’s deep dive in both and making an approach to transpiling and compiling.

Before understanding Transpiling and compiling we should make a direct focus on compiler and transpiler.

COMPILER
Compiler is the term which is used to describe a program that takes our programmable code written in a particular language and convert it into human readable format or we can say convert it into some other language.
Like we have heard about the gcc compiler which we use for compiling our source code written in C language, and produces binary executable, machine familiar as output.

TRANSPILERS
Transpilers are known as source to source compiler as its name indicates it basically transplant the same language source code into it different version set but without changing the surroundings.

For example : ES6 is latest
and ES5 is its older version, most of the browser engine support the old version of ECMA. So developers use transpiler in order to maintain the compatibility of the browser and the process is known as Transpilation.
Some of the tranaspilers are Emscripten(transpiles C/C++ to javascript), Babel (Transpiles ES6 to ES5 ).

Now we can say that compiling is a general form for moving the source code written in one language to another.
Transpiling is a specific term for transforming the source code written in one language to another language, that has a similar level of abstraction like we discussed earlier.

T.D.Z which stands for Temporal Dead Zone having a declared meaning in itself. Temporal Dead Zone sounds like a sci-fi phrase, but we should come across these three magical words to understand what the terms and concept we work with everyday. So before moving ahead let’s deep dive into these three words which are Temporal, Dead and Zone.

Temporal which indicates something like temporary, the word dead which means somehow lifeless state, and zone denotes an area which means in programming world related to memory or it can be considered as the time period or phase. So combining all these three terms narrates that some entity is temporarily in a lifeless or inactive state and can not be used for any kind of work. To understand this topic, one must have knowledge about let and const keyword in JavaScript to get it wisely. We must have a slight look over let and const and their scope in this particular section !
Const and let declarations both have block scoped, it means they are only accessible within the { } surroundings; var has no such restriction and so it is defined in a function scope.
<script>
let age = 5;
let birthday= true;
if(birthday){
let age = 6;
}
console.log(age); // 5
</script>
its output is 5 because the re-declaration of age to 6 is only available inside the curly braces. Hence “let” keyword has a block scope.
Likewise :
<script>
var age = 5;
var birthday= true;
if(birthday){
var age = 6;
}
console.log(age); // 6
</script>
now its output is 6, this is because “var” keyword has a global scope and it accesses the re-initialization of variable with different value.

DECLARATION & INITIALIZATION

Declaration of a variable states that we are allocating memory for that variable, while initialization states that we are assigning some value to the variable.

Again coming to TDZ, you might be thinking that why there is need to access any variable before initialization ?? Its true and is a wrong practice but has a specific reason of letting the developers write good code and make debugging easy in regard of let and const keyword.

Let’s us understand TDZ closely :
<script>
console.log(x);// undefined
var x= 6;
console.log(x); //6
</script>
Here global execution context is created and memory is allocated to x; means x got a place in memory and JS engine puts undefined, now thread execution phase starts during this console.log statement executes ans prints the value store in x, which is undefined.
Now in the next line there is x assigned to 6, and the undefined value of x gets replaced by 6.
Now using the some code in regard of let and const :
<script>
console.log(x);
console.log(z);
var x=6;
let z = 4;
console.log(x);
console.log(z);
</script>
// undefined
// referenceError : can’t access z before initialization
Again first of all the global execution context will be created, and the memory allocation phase starts, during this the variable x puts undefined there. Sooner z gets a space in different place of memory and same as x undefined will be assigned as value. Now the thread execution phase starts, during this console.log(x) statement executes ans prints the value of x, which is undefined.
Coming to the next line, there is console.log(z) javaScript will throw reference error in this case and program will be stopped(causing tdz).

“So we can say that TDz is the time since when this let variable was hoisted and till it is initialized some value, the time between them is known as Temporal Dead Zone”

Thank you !

Originally JavaScript was named as Mocha then as Livescript and now we are here to know the history of JavaScript and we have known about its 60% of history; congrats !

WHY ECMA ??

Discussed earlier as JS got a new position late on 1997 and due to its rapid growth, it became clear that this language needs a proper management technique and hence Netscape again won the war, handed the work of creating specified language to European Computer Manufacturers Association ( ECMA ) once again congrats; we know its full form !
Maths’ lover can differentiate ECMA to get its shorter version ES and choose the type of your version, Lol !
Between 1997 and 1999, ECMA-262 had three revisions, but nearly 10 years later its different version paced in the market which comes as something interesting to the controversial features such as generators , iterators as destructuring assignments which have been included in recent ECMAScript4.

HOW JS GOT A BOOSTER …

2005 was a big celebrations for JavaScript. A paper released by Jesse James Garrett who introduced Ajax, which proved to be revolutionary suit of technology that included JavaScript. AJAX vastly improved user experience by allowing web pages to feel more like native desktop apps and this JavaScript got a spotlight as a professional programming language.

JAVASCRIPT TODAY

From its slightly rocky start, JavaScript has risen to be the most popular programming language in the world. As per the GitHub Octoverse report in 2018, there are more JavaScript repositories than any other languages.

Thank You !

This pic shows the relativity and connection between jdk, jre and jvm.
Java Development kit is basically a package, a set of files. It provides an environment to develop and and run the java program. It consists things like development tools, provides and environment to develop our program. If we want to write some java program or need to create some application program simply we need JDK for it. It contains all those libraries and things we require. It also consists java runtime environment as we can see in the above pic like it is JDK = JRE + Development tools. In short Java runtime environment is used to run our program. So overall if we want to develop our program JDK is required as it contains different type of development tools. JRE which means Java Runtime Environment is an installation package set of files and stuffs which provides environment to only run the program which consists of different packages installed in it.

It provides an environment to create a java program. It consists of deployment technologies, user interface toolkits, integration libraries, base libraries and java virtual machine(JRE = JVM + libraries classes). After we get “.class file”, the next process done at runtime. Class loader loads all classes needed to execute the program. JVM needs code to byte code verifier to check the format of the code.
HOW JAVA RUNTIME ENVIRONMENT WORKS

It reads “.class” file and generate binary data. An object of this class is created in heap. JVM verifies the “.class file”. It allocates memory for class variable & default values. It replaces symbolic reference from the type with direct references. It initializes all static variables which are assigned with their values defined in the code and static block. JVM contains the stack and Heap memory allocation. On the other hand we can say that JRE is more like a box and there is the actual content inside the box, whatever work is being done by JVM, it is possible because of JRE whatever libraries, files and everything that JVM needs; JRE provides these things. JRE contains all these libraries as well as it contains some extra files that JVM uses in order to do dome extra work.
Java Source Code → JDK [compilation process is done here] → (.class file)Byte code → JVM ←→JRE
JVM does all the work and whatever it needs, it asks to JRE for it.
Before reading this blog I suggest you to read its first part; link is given above !
THANK YOU
by AJIT SHARMA

So all the code that we write is in java file having extension .java (pronounced as dot java). We will be writing the java code and the java file has the extension of “.java”. Now let’s go to somewhere else; in c and cpp (c plus plus); we give the code to compiler (software program in our system) →the roll of compiler is to take entire code file and convert it into the machine code format 0’s & 1’s. Java is different from them. Java too has a source code (.java file) and its compiler converts the entire file into something called byte code ( .class file). It doesn’t directly convert into the machine code. The extension of that particular byte code file is “.class”, that means when we take a .java file and compile it ; it gives .class file which contains byte code. What is this byte code??
This is something intermediate language of java or we can say alien language ( byte codes are compact numeric forms, constants, and references normally numeric addresses)!
Why do we have this byte code ?? Another good questions !!
This java code can’t directly run on the system. We need java virtual machine (JVM) to run this; and once JVM runs this byte code, it get converted into the machine code.
HAVE A LOOK HERE : →
.java file(readable format) →compiler →.class file(byte code) →interpreter(step by step) →machine code(0’s and 1's)
Not getting interpreter !=> Interpreter means it executes instructions written in a programming language without previously converting them to an object code or machine code. Python is an interpreted language, code is executed line by line.
Now from the above representation we may have a little amazement that something different language is formed in the form of byte code at a middle stage which is interpreted line by line through JAVA VIRTUAL MACHINE (JVM) and this is how it converts “.java” file into machine code. In c or cpp that middle part doesn’t exist. This is the reason JAVA is platform independent.
Platform independent means that byte code can run on all operating systems: that is wow…. !!
THANK YOU
by AJIT SHARMA