What To Use For Data Only Objects In Typescript Class Or Interface

When working with TypeScript, you may often come across situations where you need to define classes or interfaces for data only objects. These objects typically hold data without any associated methods or functionality. So, what should you use when you encounter such a scenario? Let's explore some best practices for effectively working with data-only objects in TypeScript.

### Classes vs. Interfaces

When deciding whether to use a class or an interface for data-only objects in TypeScript, it's essential to consider the main differences between the two. Classes are primarily used for defining and creating instances of objects, while interfaces are used for type-checking.

If your data-only object does not require any methods or constructor functions, using an interface is generally more appropriate. Interfaces provide a way to define the shape of an object without generating any additional JavaScript code during compilation.

interface UserData {
  id: number;
  name: string;
  email: string;
}

On the other hand, if you foresee the need to include methods or additional functionality in your data-only object, defining a class might be more suitable. However, keep in mind that including unnecessary methods in a class can lead to code clutter and confusion.

### Readonly Properties

In TypeScript, you can use the `readonly` modifier to create properties that cannot be changed once they are set. This is particularly useful for data-only objects where you want to ensure that the values remain constant throughout the object's lifecycle.

interface UserData {
  readonly id: number;
  readonly name: string;
  readonly email: string;
}

By marking properties as `readonly`, you prevent accidental changes to the object's data, enhancing the reliability and predictability of your code.

### Using Type Aliases

Type aliases in TypeScript allow you to create custom type names for complex types, making your code more readable and maintainable. When working with data-only objects, defining a type alias can help simplify your code and improve its clarity.

type UserData = {
  id: number;
  name: string;
  email: string;
}

By using type aliases, you can easily reuse complex type definitions across different parts of your codebase, reducing duplication and enhancing consistency.

### Partial Types

In some cases, you may need to work with data-only objects where not all properties are required to have a value. TypeScript provides the `Partial` utility type, which allows you to mark all properties in a type as optional.

type PartialUserData = Partial;

const user: PartialUserData = { id: 1 };

By using `Partial`, you can create flexible data structures that can be incrementally populated with values as needed, providing a convenient way to work with data-only objects that may have optional properties.

In conclusion, when dealing with data-only objects in TypeScript, consider using interfaces for simple data structures without methods and classes for more complex objects with additional functionality. Leverage features like `readonly` properties, type aliases, and `Partial` types to create robust and maintainable code. By following these best practices, you can effectively manage and manipulate data-only objects in your TypeScript projects.