What are the differences between type aliases and interfaces in TypeScript?

What are the differences between type aliases and interfaces in TypeScript?

Type aliases and interfaces are both used to define types in TypeScript, but they have some key differences. Type aliases can represent any valid type, including primitives, unions, and tuples, while interfaces are specifically for defining object shapes.

Can you give me an example of when to use a type alias instead of an interface?

Sure! Use a type alias when you need to define a union type. For example, type ID = string | number; allows you to use either a string or a number as an ID.

Are there any scenarios where interfaces are preferred over type aliases?

Yes, interfaces are preferred when you want to extend or implement them in classes. They support declaration merging, which allows you to add new properties to an existing interface.

Can I use both type aliases and interfaces together?

Absolutely! You can use both in your TypeScript code. For instance, you can define an interface for an object and a type alias for a union of types.

What about performance? Is one better than the other?

In terms of performance, there is no significant difference between type aliases and interfaces. The choice usually comes down to readability and the specific use case.