In TypeScript, both interface and type are used to define shapes or structures for values. They are often used interchangeably, but there are some subtle differences between them.

Interfaces:

1. Declaration Merging:
   • Interfaces support declaration merging. This means that if you define two interfaces with the same name, TypeScript will merge them into a single interface. This allows you to spread the definition of an interface across multiple files.

   interface Person {
     name: string;
   }

   interface Person {
     age: number;
   }

   const john: Person = {
     name: 'John',
     age: 25,
   };

1. Extending:
   • Interfaces can extend other interfaces using the extends keyword.

   interface Shape {
     color: string;
   }

   interface Square extends Shape {
     sideLength: number;
   }

   const square: Square = {
     color: 'red',
     sideLength: 5,
   };

Types:

1. Union and Intersection:
   • Types can be used to create union and intersection types more easily.

   type Status = 'active' | 'inactive';
   type Employee = {
     id: number;
     name: string;
   };

   type EmployeeStatus = Employee & { status: Status };

1. Mapped Types:
   • Types allow the use of mapped types, which can dynamically create new types based on the properties of an existing type.

   type Partial<T> = {
     [P in keyof T]?: T[P];
   };

   interface Person {
     name: string;
     age: number;
   }

   type PartialPerson = Partial<Person>;

1. Tuple Types:
   • Types can represent tuples with specific element types and lengths.

   type Point = [number, number];

   const coordinates: Point = [10, 20];

In general, interfaces are often preferred for defining object shapes, while types are more versatile and can be used for a wider range of scenarios. The choice between them often comes down to personal preference or specific use cases. It's common to see a mix of interfaces and types in a TypeScript codebase.

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