TypeScript Factory Method Example

🎓 Top 15 Udemy Courses (80-90% Discount): My Udemy Courses - Ramesh Fadatare — All my Udemy courses are real-time and project oriented courses.

▶️ Subscribe to My YouTube Channel (178K+ subscribers): Java Guides on YouTube

▶️ For AI, ChatGPT, Web, Tech, and Generative AI, subscribe to another channel: Ramesh Fadatare on YouTube

This post shows how to use the Factory Method Pattern in TypeScript with an example. 

The factory method is a creational design pattern that solves the problem of creating product objects without specifying their concrete classes.

Factory Method Structure

Factory Method Example

Let's define an interface for creating an object, but let subclasses decide which class to instantiate. Factory Method lets a class defer instantiation to subclasses.

Let's create a file named "factory-method.ts" and add the following code to it:

interface Product {
    doSomething(): void;
}

interface Factory {
    createProduct(name: string): Product;
}

class ConcreteProductA implements Product {
    doSomething(): void {
        console.log('Product A do this');
    }
}

class ConcreteProductB implements Product {
    doSomething(): void {
        console.log('Product B do this');
    }
}

class ConcreteProductC implements Product {
    doSomething(): void {
        console.log('Product C do this');
    }
}

class ProductFactory implements Factory {
    createProduct(name: string): Product {
        switch (name) {
            case 'product-a':
                return new ConcreteProductA();
            case 'product-b':
                return new ConcreteProductB();
            case 'product-c':
                return new ConcreteProductC();
            default:
                return null;
        }
    }
}

(function main() {
    const factory = new ProductFactory();
    const productA = factory.createProduct('product-a');
    productA.doSomething();

    const productB = factory.createProduct('product-b');
    productB.doSomething();

    const productC = factory.createProduct('product-c');
    productC.doSomething();
})()

Run:

1. Compile the above code using the TypeScript compiler.
2. Above code is compiled to plan JavaScript code
3. Run Javascript code using node

C:\typescript-design-patterns\factory-method> tsc .\factory-method.ts
C:\typescript-design-patterns\factory-method> node .\factory-method.js

Output:

Product A do this
Product B do this
Product C do this

The above "factory-method.ts" file compiled into below plan JavaScript code by TypeScript compiler:

var ConcreteProductA = /** @class */ (function () {
    function ConcreteProductA() {
    }
    ConcreteProductA.prototype.doSomething = function () {
        console.log('Product A do this');
    };
    return ConcreteProductA;
}());
var ConcreteProductB = /** @class */ (function () {
    function ConcreteProductB() {
    }
    ConcreteProductB.prototype.doSomething = function () {
        console.log('Product B do this');
    };
    return ConcreteProductB;
}());
var ConcreteProductC = /** @class */ (function () {
    function ConcreteProductC() {
    }
    ConcreteProductC.prototype.doSomething = function () {
        console.log('Product C do this');
    };
    return ConcreteProductC;
}());
var ProductFactory = /** @class */ (function () {
    function ProductFactory() {
    }
    ProductFactory.prototype.createProduct = function (name) {
        switch (name) {
            case 'product-a':
                return new ConcreteProductA();
            case 'product-b':
                return new ConcreteProductB();
            case 'product-c':
                return new ConcreteProductC();
            default:
                return null;
        }
    };
    return ProductFactory;
}());
(function main() {
    var factory = new ProductFactory();
    var productA = factory.createProduct('product-a');
    productA.doSomething();
    var productB = factory.createProduct('product-b');
    productB.doSomething();
    var productC = factory.createProduct('product-c');
    productC.doSomething();
})();

My Top and Bestseller Udemy Courses. The sale is going on with a 70 - 80% discount. The discount coupon has been added to each course below:

Build REST APIs with Spring Boot 4, Spring Security 7, and JWT

🆕 High-Demand 80–90% OFF

[NEW] Learn Apache Maven with IntelliJ IDEA and Java 25

🆕 High-Demand 80–90% OFF

ChatGPT + Generative AI + Prompt Engineering for Beginners

🚀 Trending Now 80–90% OFF

Spring 7 and Spring Boot 4 for Beginners (Includes 8 Projects)

🔥 Bestseller 80–90% OFF
Available in Udemy for Business

Building Real-Time REST APIs with Spring Boot - Blog App

🔥 Bestseller 80–90% OFF
Available in Udemy for Business

Building Microservices with Spring Boot and Spring Cloud

🌟 Top Rated 80–90% OFF
Available in Udemy for Business

Java Full-Stack Developer Course with Spring Boot and React JS

🔥 Bestseller 80–90% OFF
Available in Udemy for Business

Build 5 Spring Boot Projects with Java: Line-by-Line Coding

🌟 Top Rated 80–90% OFF

Testing Spring Boot Application with JUnit and Mockito

🔥 Bestseller 80–90% OFF
Available in Udemy for Business

Spring Boot Thymeleaf Real-Time Web Application - Blog App

🔥 Bestseller 80–90% OFF
Available in Udemy for Business

Master Spring Data JPA with Hibernate

🔥 Bestseller 80–90% OFF
Available in Udemy for Business

Spring Boot + Apache Kafka Course - The Practical Guide

🎓 Student Favorite 80–90% OFF
Available in Udemy for Business

Java Testing: Mastering JUnit 5 Framework

🆕 New 80–90% OFF

Reactive Programming in Java: Spring WebFlux and Testing

🌟 Top Rated 80–90% OFF

Spring Boot + RabbitMQ Course - The Practical Guide

🌟 Top Rated 80–90% OFF
Available in Udemy for Business

Functional Programming in Java (Includes Java Collections)

🎓 Student Favorite 80–90% OFF

ChatGPT for Java Developers: Boost Your Productivity with AI

🚀 Trending Now 80–90% OFF