Typescript automatically get interface properties in a class

Question

Hello TypeScript experts.

I have the following code but I have to repeat the interface properties in the class otherwise I get:

Class incorrectly implements interface

When using an interface, is there a TypeScript shorthand for doing this without having to declare Id: number; and all the other properties in the class? Thx

interface INavigation {
  Id: number;
  AppId: number;
  NavId: number;
  Name: string;
  ParentId: string;
  PageURL: string;
  Position: string;
  Active: string;
  Desktop: string;
  Tablet: string;
  Phone: string;
  RoleId: string;
  Target: string;
}

class Navigation implements INavigation {

  Id: number;
  AppId: number;
  NavId: number;
  Name: string;
  ParentId: string;
  PageURL: string;
  Position: string;
  Active: string;
  Desktop: string;
  Tablet: string;
  Phone: string;
  RoleId: string;
  Target: string;

  constructor(navigation: any) {
    this.Id = navigation.Id
    this.AppId = navigation.NavAppId
    this.NavId = navigation.NavId
    this.Name = navigation.NavName
    this.ParentId = navigation.NavParentId
    this.PageURL = navigation.NavPageURL
    this.Position = navigation.NavPosition
    this.Active = navigation.NavActive
    this.Desktop = navigation.NavDesktop
    this.Tablet = navigation.NavTablet
    this.Phone = navigation.NavPhone
    this.RoleId = navigation.NavRoleId
    this.Target = navigation.NavTarget
  }
}

Answer 1

This is now possible in Typescript using class/interface merging.

interface Foo {
    a: number;
}

interface Baz extends Foo { }
class Baz {
    constructor() {
        console.log(this.a); // no error here
    }
}

https://github.com/Microsoft/TypeScript/issues/340#issuecomment-184964440