The Factory Method pattern in TypeScript

Hi!

The Factory Method pattern is a design pattern that is used to create objects without specifying the exact class of object that will be created. It is often used when the type of object to be created is determined at runtime, or when there is a need to create objects of different types based on the specific requirements of the application.

In TypeScript, the Factory Method pattern can be implemented using a factory function that takes a set of parameters and returns an object of a specific type. The factory function uses the parameters to determine the type of object to create, and then creates and returns the object.

Here is an example of a factory function in TypeScript:

function createProduct(type: string): Product {
  switch (type) {
    case 'book':
      return new Book();
    case 'software':
      return new Software();
    default:
      throw new Error('Invalid product type');
  }
}

This factory function takes a type parameter that specifies the type of product to create. It then uses a switch statement to determine the type of object to create based on the type parameter. If the type parameter is book, the factory function creates and returns a Book object. If the type parameter is software, the factory function creates and returns a Software object. Otherwise, it throws an error.

To use the factory function, other classes can call it with the appropriate type parameter to create an object of the desired type.

Here is an example of how to use the factory function:

const product = createProduct('book');

In this example, the createProduct function is called with the type parameter set to book, which causes the factory function to create and return a Book object.

The Factory Method pattern is a useful design pattern for creating objects without specifying their exact class. In TypeScript, it can be implemented using a factory function that takes parameters and returns an object of the appropriate type. This allows other classes to create objects of different types based on the specific requirements of the application.