https://grokonez.com/design-pattern/implement-simple-factory-method-pattern-node-js-example

How to implement simple Factory Pattern in Node.js

Instead of using class constructors or new keyword to create an object of a class, we can abstract this process. So, we can determine the type of object at run-time, by the time of generating that class object. The implementation seems like Factory Method, but simpler than Factory Method. This simple Factory is not treated as a standard GoF design pattern, but the approach is common to any place where we want to separate the code that varies a lot from the code that does not vary.

In this tutorial, grokonez shows you how to do it in NodeJs.

Nodejs simple Factory Pattern example

Overview

In this example, we have 3 types of cars: Audi, BMW, Mercedes. The car generating process depends on the input string "Audi" or "BMW" or "Mercedes".

CarFactory is the Factory class. In the client, we won't use new keyword but create() method to create a new car:

const BMW = CarFactory.create('BMW');

Sample Structure

Implement simple Factory Pattern in Nodejs

Create default class

This Car class is a parent class for Audi, BMW, Mercedes class that we're gonna create in the next steps.

default_car.js

class Car {
    constructor(name) {
        this.name = name + '-' + Math.random().toString(36).substring(2, 15);
    }

    showInfo() {
        console.log(`I'm ${this.name}`)
    }
}

module.exports = Car;

This class has constructor method that assign a generated id to the car's name and a showInfo() method to show the name field.

Create subclasses of default class

Now we create 3 classes: Audi, BMW, Mercedes that extends default Car class above.

More at:

https://grokonez.com/design-pattern/implement-simple-factory-method-pattern-node-js-example

How to implement simple Factory Pattern in Node.js