GIT FOR A BEGINNER

JaswanthReddyPadala — Wed, 25 Nov 2020 13:04:49 +0000

GIT?

Git was created by Linus Torvalds in 2005 for the development of the Linux kernel, with other kernel developer team. Git is a distributed version control tool. In simple language, Git is like a record book, it keeps on tracking your files and changes made in project files.

WHY GIT?

Although there are dozens of version control systems on the market like CVS, SVN, Mercurial, Bazaar, etc. But let's know what makes git more popular and powerful?

Save time
Git is a cool and very fast tool. Simple commands save us a lot of time. We can easily push codes and it improves team collaboration.
Offline
Git can also be used in offline mode expect when you try to push your code to an online repository or cloud. But if you're using CVS you need to be connected to the central repository. This is not the case with git, you can happily do everything in your local machine itself like add, make commits, merge or create branches, push your codes, and many actions as you explore.
Undo or Redo mistakes
Generally, people make mistakes. It is one of the features in git is like a undo command. If you have messed up your code at some point in time then you can "undo" and go back in time in sense of code where you have a working code in the commit history. You can even restore disappeared commits. Awesome right?.
Clone a project
If you ever see a good project in someone's repository and if you want to work on it and make your own version of that project. Git gives the functionality of cloning the project without deleting anything from the original repository. It copies whole files in someone's repository to your local machine and any changes you made in those files don't affect the original repository.
Commits
A commit is really useful if it contains related changes. When you change or add some feature you give a commit message and explaining about the change you committed in a meaningful way. For example, the person is adding a new feature 'A' he can commit something like "added feature A". In case the feature 'A' is not working properly we can revert back to the code before adding this new feature.
Don't touch working code
While you’re working on the feature 'A', What will be the situation if the new feature 'A' is not needed after making several commits to the main code. While developing a working code, nothing else should be affected by your unfinished code. To deal with this kind of situation Branching is the only option. Using this feature, we can create a new branch to the main code without disturbing the main code. And later if the new code perfectly fits and works with then we can merge this branch with the main branch to develop a fully working code with the new feature 'A'.

So why late, start learning how to this awesome tool and use git

Resources: Git book | Git cheat sheet

Leave you thoughts in the comment section

Thank you for reading 🙏
Jaswanth Reddy Padala - Email | Linkedin | Twitter

START LEARNING JS

JaswanthReddyPadala — Wed, 18 Nov 2020 12:36:39 +0000

LEARN JAVASCRIPT BASICS

Learn to appreciate yourself and celebrate small wins --- This helps you keep on motivating

Basics of Javascript

1. Introduction

JavaScript ("JS" for short) is a full-fledged dynamic programming language that can add interactivity to a website. It was invented by Brendan Eich (co-founder of the Mozilla project, the Mozilla Foundation, and the Mozilla Corporation) Click here, to know the complete history of Javascript till now.

2. Hello World!

console.log("Hello World!");

//console.log() is one of the javascript inbuilt function which allows us to print anything in the code at the output.

3. Input from user

prompt is an inbuilt function in javascript which creates a dialogue box to enter user input. But this works only in the browser console. This method of taking input is not suggested but learn its existence.

prompt("What is your name?");

4. Variables

Javascript contains containers which store the values called Variables

var myName = "Jaswanth";
var myAge = 19;
let myPlace = "Rajahmundry";
.
.
.
//many things were there to know about these variables, so go through the above link.

5. Data types in JS

Different kinds of data were names with different names. Data types like integer, string, character, float, booleans. And in advanced Array, and many more. We learn them on the go.

Apart from these, you should also know about type coercion

var integer= 723; // It is a Integer(number);
var deciamalNumber = 200.76349; //It is a Float(decimal number)
var str = "Javascript is a scripting language."  //It is String(text)
let bool = True //Boolean (True or False)

6. Conditional statements

if statement :: To check whether a condition is satisfied to execute a part of the code.

if-else :: It behaves like if the condition in if the statement is true then the code execute the part enclosed within if or else it runs the part which
is enclosed within else statement.

nested-if :: If an if the statement is true then it checks for the next if statement which is inside an if statement.

if - else if - else :: This is like if a condition is not true if check another if statement outside if statement.

if statement

// if statement-syntax

var myAge = 19;
if(check_condition){
    //if true execute statements inside this
}


//if statement - example

if (myAge >=18){
    console.log("you are above 18);
}

if-else

//if-else  - syntax

if(check_condition){
    //if true execute statements inside this
}
else{
    //if false execute statements inside this
}


//if-else  - example

var myAge = 16;
if (myAge >= 18){
    console.log("you are above 18);  //does not execute this
}
else{
    console.log("you are below 18);  //executes and prints "you are below 18"
}

nested if

//syntax

if(check_condition-1){
    //if true
    if(check-condition-2){
        //if true
        if(check-condition-3){
            ... // this goes on till every check condition is true
        }
    }
}

* if any of the check condition is false it comes out and executes the rest of the statements below that if statement. *

//example
var myAge = 19;
var myName = "Jaswant";
if(myAge >= myAge){     //condition is true
    if (myName == "Jaswanth"){ //condition is false
        console.log("You are Jaswanth");
    }
    console.log("You are",myAge);
}

output -
You are 19

Loops

Developers follow the "DRY" principle which means - DO NOT REPEAT YOURSELF. So they make use of loops, functions, algorithms, patterns, and many more. Now we can learn what are loops.
Looping is the concept of running a set of statements multiple times until the conditions inside looping statements become false.
Refer here to learn about different types of loops.

for loop

for - syntax

for(INITIALIZATION, CHECK_CONDITION, INCREMENT/DECREMENT){
    //set of statements to be executed
}

for - example

for(let i=0; i<5; i++){
    console.log("hello..");
}

// let i = 0  -->  initialize i = 0;
// i<5 --> checks wheather the value of i is less than 5
// i++ --> increment the value of i by 1 value(i=i+1)
//This loop runs for 5 times and print "hello.."
hello..
hello..
hello..
hello..
hello..

while

while - syntax

//
while(CHECK_CONDITION){
    //set of statements to be executed
}

while - example

var i = 0;
while(i<5){
    console.log("hello..");
    i++;
}

//This loop runs 5 times and print "hello.."
hello..
hello..
hello..
hello..
hello..

do while -- This is a special type of while loop in which initially the loop will run at least for one time even though the condition is not satisfied.

do-while  - syntax
do{
    //set of statements to be executed
}while(CHECK_CONDITION);

//do-while  - example
let k=10;
do{
console.log(k);
k++;
}while(k<0)

//output -
10

Functions

Functions were used to perform a specific set of functions by passing input and getting outputs from it. We can call the function multiple times with different inputs and perform the same task and get different outputs each time(different inputs).

//defining a function - syntax
function FUNCTION_NAME(PARAMETERS){    //parameters are the optional inputs which were received by the function to do something with them and give output
    //set of statements to be executed when function is called
}

//function calling - syntax
FUNCTION_NAME(ARGUMENTS); //argumentss are the optional values which were to be passed to functions as inputs for that function

//example
function printName(name){  //name is parameter
    console.log("Hi " + name);
}

//calling a function
printName("Tanay");     // Tanay is an argument --> this print :  "Hi Tanay"
printName("Akanksha");     // Akanksha is an argument--> this print :  "Hi Akanksha"

Setting up the project

Go to repl (explore repl, it is an interesting web app to use).
Now, if you are new to repl then create a new account.
Open a new repl and select node.js under node.js
Now you will enter into Javascript with node.js console.
Don't get confused it will take time to get used to it. Explore repl in your free time.

Quiz project

Now, let's get into our simple javascript and nodejs project. In this simple project, we build a simple Command Line Interface quiz. Eventually while doing the project let us build our project.

What we will be learning by doing this project?

Taking inputs (using 'readline-sync' npm package)
Printing output
Using operators
Usage of if and if-else
Usage of for loops
Usage of basic data structures like arrays, dictionary

The objective of creating this project is to create a quiz about MARVEL

For taking user inputs we use a npm package called 'readline-sync'

To use this package in your library type the below code to make it available for our project.

var readlineSync = require('readline-sync')

Now input the player_name and print the welcome message. '\n' is an escape character. Know about escape characters in strings.

var playerName = readlineSync.question("Enter your name: ");
console.log("Welcome to the quiz ",playerName+"\n");

Now initialize player_score

var playerScore = 0;

Let's create a sample array of 3 questionobjects

const generalQuiz = [
    {
        question: "Who is the prime minister of india?",
        a: "Tanay Pratap",
        b: "Bumrah",
        c: "Narendra Modi",
        d: "Dhoni",
        correctAnswer: "c"

    },
    {
        question: "Who is the president of america?",
        a: "Jaswanth",
        b: "James Cameron",
        c: "Kamala Harris",
        d: "John Beiden",
        correctAnswer: "d"
    },
    {
        question: "Which is the largest continent?",
        a: "Asia",
        b: "Africa",
        c: "South America",
        d: "Europe",
        correctAnswer: "a"

    },
]

Wow, we used arrays and objects as each item in an array. Now we need to print these questions for our player. So we use for loop to it now.

We need to use for loop to iterate over each and every question and only if the answer is correct we can add 1 to player_score.

// we declare function so that the function playQuiz takes in different objects but conducts and evaluate quiz

function playQuiz(quiz){
    for (let i = 0; i < quiz.length; i++)
    {
        console.log(`${i + 1}. ${quiz[i].question}`);
        console.log(`          a: ${quiz[i].a}`);
        console.log(`          c: ${quiz[i].b}`);
        console.log(`          b: ${quiz[i].c}`);
        console.log(`          d: ${quiz[i].d}`);
        var answer = readlineSync.question("Answer: ");
        console.log("\n");

        //now validate answer
        if (answer.toLowerCase() == quiz[i].correctAnswer){
        playerScore = playerScore + 1;
        }
    }
    return playerScore;
}

Now each time the player answers correctly the score increases.

Now finally print the user's score at last.

let finalScore = playQuiz(generalQuiz); // here we called the playQuiz function and stored the final score of the player in finalScore variable.

console.log("Woohooo!!, you scored "+finalScore);   // printing final score.

OUTPUT

YAY!! you have done a CLI project, Though it is simple this will help you in building your fundamentals well.
Hope you learned the basics OF javascript

DEV Community: JaswanthReddyPadala