How To Create Abstract Base Class In Javascript That Cant Be Instantiated

Abstract classes are a fantastic way to structure your code in JavaScript, providing a blueprint for other classes to inherit from. But what if you want to take it a step further and ensure that your abstract base class cannot be directly instantiated? In this article, we will explore how you can create an abstract base class in JavaScript that cannot be instantiated.

To achieve this in JavaScript, we will make use of a combination of features including ES6 classes and the concept of abstract classes. While JavaScript does not have built-in abstract class support, we can emulate this behavior by leveraging certain patterns and concepts.

Firstly, let's define our abstract base class using ES6 class syntax. To indicate that the class is abstract, we will throw an error in the constructor if an attempt is made to instantiate it directly. Here's an example of how you can create an abstract base class in JavaScript:

class AbstractBaseClass {
    constructor() {
        if (new.target === AbstractBaseClass) {
            throw new Error("Cannot instantiate abstract class");
        }
    }

    // Add any abstract methods or common functionality here
}

In the constructor of the `AbstractBaseClass`, we check if the `new.target` property is equal to the class itself. If it matches, it means that someone is trying to directly instantiate the abstract class, which is not allowed. In such cases, we throw an error to prevent instantiation.

Next, let's demonstrate how to create a concrete class that extends our abstract base class. When extending the abstract class, we provide implementations for any abstract methods defined in the base class. Here is an example:

class ConcreteClass extends AbstractBaseClass {
    constructor() {
        super();
        // Perform any initialization here
    }

    // Implement abstract methods
}

In the `ConcreteClass`, we extend the `AbstractBaseClass` and provide the necessary implementations for any abstract methods. By calling `super()` in the constructor, we ensure that the abstract class's constructor is properly invoked.

By following this approach, you can enforce the abstraction of your base class in JavaScript and prevent direct instantiation of the abstract class itself. This enables you to define a clear hierarchy of classes and promote code reusability and maintainability within your applications.

In conclusion, creating an abstract base class in JavaScript that cannot be directly instantiated involves combining ES6 class syntax with error handling in the constructor. By leveraging these techniques, you can establish a solid foundation for your object-oriented design and ensure that your code is structured in a clear and maintainable manner.