Import and Export Javascript Functions/Files

calculator.js

// Let us assume that this is the file you are working with and you need some arithmetic functions

//below is the import statement 

const math = require("math.js")
let num1 = 10
let num2 = 20
console.log(math.add(num1,num2))     //math.add is how we will be accessing the add functions from the math.js file
                                          make sure that you pass two arguments, since add function requires two arguments.

math.js

// parent file (library/module. We will export the functions of this file

const add = (x,y) => x+y  // This function will add two numbers and return it
const subtract = (x,y) => x-y // this function will subtract two numbers and return it

//similarly create as many function as you want and export them in the belwo mentioned syntax

module.exports = {add, subtract}  //these two functions will be exported.