Typescript, using classes without constructor

Question

While working with the "Tour of Heroes" tutorial on the Angular website I found the following syntax (shortly):

class Hero {   id: number,   name: string, }  const aHero: Hero = {   id: 1,   name: 'Superman' }  console.log(aHero instanceof Hero); //false 

What would be the point in doing this? when if I check the type of "aHero", it is only a common object and not a "Hero" type. Would it be better just initializing an object with a constructor?:

class Hero {   constructor(id: number, name: string) {} } 

Answer 1

You can use class as a type which is the way you're using it. So, whether Hero is an interface or class it doesn't matter because you're using it as a type.

class Hero { id: number; name: string } 

or

interface Hero { id: number; name: string } 

The following doesn't concern whether Hero is a class or interface

let hero: Hero = { id: 1, name: 'me' } 

Where interface and class differentiate is interface is only for you, it doesn't get transpiled into javascript. A class does and you cannot new an interface.

Constructor or no Constructor, if you new it then it is an instanceof. Try it again with this

let hero = new Hero(); 

Your instanceof log will be true because you did create an instance of Hero with the key word new.