What is the difference between interface and type in Ty…

In TypeScript, both interface and type are used to define types. They share some similarities but also have some differences.

1. In terms of syntax, interfaces are defined using the keyword “interface,” while types are defined using the keyword “type.”
2. Capability to implement and inherit: Interfaces can be extended using the “extends” keyword, allowing for multiple inheritance; whereas types cannot be extended, but can achieve similar effects through intersection types (&).
3. Merging Declaration: When defining interfaces with the same name, they automatically merge; however, defining types with the same name will result in an error.
4. Compatibility: Interfaces are contravariant, meaning that when an object implements an interface, it can be assigned to that interface or its parent interface. Types are invariant, meaning that they can only be assigned to the exact same type.
5. Readability: Interfaces are more common and easier to understand in code, while types are more suitable for complex type definitions, such as union types, intersection types, and mapped types.

Overall, interfaces are used to describe the shape and structure of objects, making them more suitable for defining the types of classes, objects, and functions; while types are more suitable for defining union types, intersection types, and complex type aliases. When using them, you can choose to use either interfaces or types based on the specific situation.