In simple terms, Interfaces provide code contracts which all classes that implement the interface have to follow.
Following is a simple example for a typescript interface and a class implementing the interface.
class Dog implements IAnimal
return 'Bow bow';
var dog = new Dog();
dog.legs = 4;
The above code sample creates an interface named IAnimal which has a property and a function which all animals have. The class Dog implements from this Interface and has to provide definition for the property and the function.
feel free to play withe the code sample here .