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 (opens in a new tab)

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

2. 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

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

const arr = [1,2,3,4,5,6,7,8,9,10]
 
const greaterThan5 = arr.filter((element) => element > 5)
 
console.log(greaterThan5)
 

[ 6, 7, 8, 9, 10 ]

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

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)
 

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)