Backend development is the backbone of modern applications, ensuring functionality, scalability, and security. In this guide, we delve into everything you need to know about backend development, including:

• The role of the backend in web and mobile applications.

• Popular backend programming languages and frameworks (Node.js, Python, Java, etc.).

• Key concepts like APIs, databases, and server architecture.

• Best practices for performance optimization and secure coding.

• An overview of DevOps, cloud computing, and backend deployment.

Whether you're a beginner or looking to sharpen your skills, this blog provides insights to help you master backend development and build powerful applications.

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so let’s begin with :→

1> node js

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Node js :→

0> installing the node js :→

NODE JS (CLICK on this to install it)

after installing it . check if it’s installed or not.

node -v

it should give the version number that means we have successfully done it.

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1> hello world in js and history of it :→

hello world in js :→

console.log("hello world");

history of node js :→

At first the js code will run on all the browser with the help of js engines in the browser like (v8 engine, chrome safari) has it’s own server.

node js developer took the open-source “v8 engine” and added c++ code and made a js run-time named “node js”.

what node js help us to do ?

as node js is a run-time. It just help us to execute the “javascript” code outside of the browser with any engine now!!!

through it does not have all the things like “window” and “DOM“ but all in all it have all the things that use for server-side devlopment.

node js in non-blocking run time. means if multiple request goes to server then it will take all the request unlike php other backend framework on run-time.

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2>Modular Programming / Local modules in js :→

MODULES : —> bundles of functions/file when we use that by importing and exporting.

let’s assume we have 2 files :→

1st is “math.js” and other is “cal.js" in the math.JS we will store the all “mathematical function” like addition, substraction , multiplication and division . Now from math.js we will export the functions with

“module.exports={ all the functions } "

that’s how we export the functions as bundle now let’s see how to call them and import the modules. let’s see 👀

function add(a,b){
    return a+b;
}

function sub(a, b) {
  return a - b;
};

function multiply(a, b) {
  return a * b;

}

function division(a, b) {
  return a / b;

}

module.exports = {
  add,
  sub,
  multiply,
  division,
};

in cal.js we will import these modules. we will do it by

const {function names}=requires(“module name“)

here modules can be built-in module, 3rd party module or we can use the module the module we have made too. let’s see it in “cal.js”

const { add, sub, multiply, division } = require("./math");
console.log(add(2 , 20));
console.log(sub(10, 2));
console.log(multiply(2, 3));
console.log(division(10, 2));

“./” :—> represent the current directory in where we have made the file./

so we have learned about the local module and use them .

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3> IN build modules in node :→

a>path :→

Path for Node Module

read about it to deep dive into it.

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b> dirname (directory name) :→

// path in node
//dirname with resolve
const { log } = require('console');
const path = require('path')
const reply = path.resolve('./index.js')
const reply1 = path.dirname(path.resolve('./index.js'))
const reply2= path.dirname('./index.js')
console.log(`the total paths of this file is ${reply}`);
console.log(`the only dirname of the file is ${reply1}`);
console.log(`whats only dir will give ${reply2}`);

output :→

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c>basename => file name that given

// path in node
//base name [file name] => (extname)
const { log } = require('console');
const path = require('path');
const reply = path.basename('./astra.js');
console.log(`the extension name of this file is ${reply}`);

output :→

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d> parse => it give everything about the file and folder.

// path in node
//parse generally return an object in which ther5e is any ,ore 
const { log } = require('console');
const path = require('path');
const reply = path.parse('./astra.js');
console.log(`the parsing object name of this file is ${reply}`);
console.log(`the full name of this file is ${reply.base}`);
console.log(`the directory name of this file is ${reply.dir}`);
console.log(`the extension name of this file is ${reply.ext}`);
console.log(`the name of this file is ${reply.name}`);
console.log(`the root name of this file is ${reply.root}`);

output :→

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e>Join :→

// path in node
// join as  name suggest join whats parameter give 
//__dirname here will give the current directory
const { log } = require('console');
const path = require('path');
var x = path.join(__dirname,'order', './astra.js')
console.log(x);

output :→

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f> Join :→

// path in node
// join as  name suggest join whats parameter give 
//__dirname here will give the current directory
const { log } = require('console');
const path = require('path');
var x = path.join(__dirname,'order', './astra.js')
console.log(x);

output :→

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b> file_system(FS) :→

1>mkdir => making directory

// making a directory (in bash too)
const fs = require('fs');
const path = require('path');
fs.mkdir(path.join(__dirname, './test'), (err) => {
  if (err) {
    console.error("error has come");
    return   
  } 
  console.log("file is created");
 })

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output :→

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2> writing the file :→

// write file 
const fs = require('fs')
const path = require('path')
fs.writeFile(path.join(__dirname, './test', 'text.js'), "hello nodejs", (err) => {
  if (err) {
    console.log(err);
    throw err;
  }
  console.log("data is added!!!");  
})

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3> writing file again and again :→

const fs = require('fs');
const path = require('path');


fs.writeFile(path.join(__dirname, './text', './astra.js'), "nacho nacho \n", (err) => {
  if (err) {
    console.log(err);
    throw err;
  }
  console.log('finally file is made');
  fs.appendFile(path.join(__dirname, './text', './astra.js'), "nacho nacho pro max", (err) => {
    if (err) {
      console.log(err);
      throw err;
    }
    console.log("finally edited again!!!");

  })

 })

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c> (operating system)OS :→

1> OS Type:→