TypeScript 2.x By Example

Interface

The primary purpose of an interface is to drive code consistency. An interface is a contract defined and any class that implements the interface needs to implement all the properties of that interface. The interface is a pure TypeScript concept and is not part of ECMAScript; this means that when TypeScript code is converted to JavaScript, interfaces are not converted:

interface Planet{    name: string;    weather: string; }class Earth implements Planet {    name: string;    weather: string;}let planet: Planet= new Earth();