Extending interfaces

Interfaces can be extended. Extending an interface makes it share the properties of another interface, as follows:

interface Manager { 
    hasPower: boolean; 
} 
  
interface Employee extends Manager { 
    name: string; 
} 
  
var employee = <Employee>{}; 
employee.name = "Rajesh Gunasundaram"; 
employee.hasPower = true; 

Here, the Employee interface extends the Manager interface and shares its hasPower with the Employee interface.