• Szerző: Sallai András
• Copyright © 2021, Sallai András
• Licenc: CC Attribution-Share Alike 4.0 International
• Web: https://szit.hu

pi.js

module.exports = 3.14

app.js

const pi = require('./pi.js');
console.log(pi)

pi.js

const pi=3.14
module.exports= pi

app.js

const pi = require('./pi.js');
console.log(pi)

math.js

const pi=3.14
const e=2.718
module.exports= { pi, e}

app.js

const math = require('./math.js')
console.log(math.pi)
console.log(math.e)

math.js

const pi=3.14
const e=2.718
 
const pow = function(a,b){
  return a**b
}
 
module.exports= { pi, e, pow }

app.js

const math = require('./math.js')
console.log(math.pi)
console.log(math.pow(2,3))

Két függvényt a triangle objektumon keresztül érünk el:

triangle.js

module.exports = {
	calcPerimeter: function (sidea, sideb, sidec) {
		return sidea + sideb + sidec;
	},
	calcArea: function (base, height) {
		return base*height/2;
	}
}

app.js

const triangle = require('./triangle.js');
 
console.log(triangle.calcPerimeter(30, 35, 40));
console.log(triangle.calcArea(30, 35));

A triangle objektum. De kinyerhetem belőle a két függvényt:

app.js

const triangle = require('./triangle.js');
const calcPerimeter = triangle.calcPerimeter;
const calcArea = triangle.calcArea;
 
console.log(triangle.calcPerimeter(30, 35, 40));
console.log(triangle.calcArea(30, 35));
 
 
console.log(typeof(calcArea));

rectangleArea.js

module.exports = function(base, height) {
  return base*height;
}

app.js

const rectangleArea = require('./rectangleArea.js');
console.log(rectangleArea(30, 35));

employees.js

module.exports =  [
    { name: 'Nagy János', city: 'Hatvan' },
    { name: 'Kis Irén', city: 'Szolnok'}
  ];

app.js

const employees = require('./employees.js');
console.log(employees[0].name);

triangle.js

let maxSize = 100;
 
module.exports = {
	calcPerimeter: function (sidea, sideb, sidec) {
		if (	sidea < maxSize &&
			  	sideb < maxSize  &&
			  	sidec < maxSize)
				return sidea + sideb + sidec;
		else
				console.log("Error! Side is too large!");
	},
	calcArea: function (base, height) {
		if (base < maxSize && height < maxSize)
				return base*height/2;
		else
				console.log("Error! Side is too large!");
	}
}

Employee.js

module.exports = class Employee {
    constructor(name, city) {
      this.name = name || 'Névtelen';
      this.city = city || 'Ismeretlen';
    }
}

app.js

const Employee = require('./employee.js');
 
const janos = new Employee('Nagy János', 'Szolnok');
console.log(janos.name);
 
console.log(typeof(Employee));
console.log(typeof(janos));

Az Employee függvényként jelenik meg, de a janos már objektumoként.

• https://nodejs.org/docs/latest/api/module.html (2025)
• https://www.hacksparrow.com/nodejs/writing-modules.html (2021)
• https://initialcommit.com/blog/nodejs-module (2021)
• https://docs.npmjs.com/creating-node-js-modules (2021)
• https://www.digitalocean.com/community/tutorials/how-to-create-a-node-js-module (2021)
• https://www.freecodecamp.org/news/modules-in-javascript/ (2025)