SarveshKadam

// - - Exported file [calculate.js] - - 
const add = (a,b)=>{
 return a + b
}
module.exports = add

SarveshKadam

// - - - Main File[main.js] - - 

const add = require('./calculate') //name of the desired file
const result = add(2,4)
console.log(result); //Output : 6

SarveshKadam

// - - Exported file [calculate.js] - - 
const add = {
 result : (a,b)=>{
 return a + b
 }
}
module.exports = add

SarveshKadam

// - - Main file[main.js] - - 

const add = require('./calculate')
const result = add.result(5,8)
console.log(result) //Output : 13

SarveshKadam

// - - Exported file [calculate.js] - - 

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

SarveshKadam

// - - Main file[main.js] - - 

const add = require('./calculate')
const result = add(5,8)
console.log(result) //Output : 13

SarveshKadam

// - - Exported file [calculate.js] - - 

function Add (){
    this.result = (a,b)=>{
        return a + b
    }
}

module.exports = new Add()

SarveshKadam

// - - Main file[main.js] - - 

const add = require('./calculate')
const result = add.result(2,1)
console.log(result); //Output : 3

SarveshKadam

// - - Exported file [calculate.js] - - 

const Add = class{
  constructor(a,b){
     this.a = a;
     this.b = b;
     }    
  result(){
    return this.a + this.b
   }

SarveshKadam

// - - Main file[main.js] - - 

const add = require('./calculate')
const result = new add(2,5)
console.log(result.result()); //Output : 7