Fundamentals and Features of Node.js

Hi, I'm Subham Maity, a software engineer. I also enjoy teaching others how to code through my tutorials. I'm always eager to learn new things and share my knowledge with the community.

⚡ I recently wrote an article on Fundamentals and Features of Node.js and wanted to share it with you all. You can find the article on my website https://codexam.vercel.app/docs/node/node1 [Better View]

⚡ I also have a repository on GitHub where you can find all the code and projects related to this topic. You can find the repository at https://github.com/Subham-Maity/node-js-full-stack-tutorial

❗ For a more in-depth look at this topic, including a detailed table of contents, check out the complete tutorial on my GitHub Repo

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For NodeJs you need to have a basic knowledge of Javascript. If you are new to Javascript then you can check out my tutorial on Javascript

Some Important Notes

1. Suppose you make a file app.js and another file index.js and you want to import the app.js file like this

export const name = "Subham Maity"
export const age = 20

import {name,age} from "./app.js"

And in your terminal you run node index.js then you will get an error like this

SyntaxError: Cannot use import statement outside a module

This is because NodeJs doesn't support the import and export syntax. So you have to use the module.exports and require syntax.

module.exports = {
    name: "Subham Maity",
    age: 20
}

const {name,age} = require("./app.js")

console.log(name,age)

Now if you run node index.js then you will get the output like this.

Subham Maity 20

1. You can even create a function in app.js and export it and then import it in index.js and use it.

module.exports = {
    add: (a,b) => a+b
}

const app = require("./app.js")

console.log(app.add(2,3))

Now if you run node index.js then you will get the output like this

5

What is filter in JavaScript ?

• If you have an array like this

const arr = [1,2,3,4,5,6,7,8,9,10]

and you want to traverse through the array and get the elements which are greater than 5 then you can use the filter method.

const arr = [1,2,3,4,5,6,7,8,9,10]

const greaterThan5 = arr.filter((element) => element > 5)

console.log(greaterThan5)

Now if you run node index.js then you will get the output like this.

[ 6, 7, 8, 9, 10 ]

• If you have an array like this

const arr1 = [1,2,3,4,4,4,5,6,7,8,9,10]

and you want to traverse and find the value that is repeated the most then you can use the filter method.

const arr1 = [1,2,3,4,4,4,5,6,7,8,9,10]

const mostRepeated = arr1.filter((element) =>
{
    return element === 4
})

console.log(mostRepeated)

Even you can do greater than 5 and less than 8

const arr1 = [1,2,3,4,4,4,5,6,7,8,9,10]

const mostRepeated = arr1.filter((element) =>
{
    return element > 5 && element < 8
})

console.log(mostRepeated)