Javascript: Object.assign to assign property values for classes is not respected

Perhaps TS should be able to identify Object.assign(this, ...) then infer the properties that are assigned to this? Or is this not possible to do? I am not sure.

TypeScript Version:
Version 3.0.3

Search Terms:

• object assign
• class
• does not exist on type

Code
A.js

export default class A {
  constructor ({ x, y, z }) {
    Object.assign(this, {x, y, z});
  }
  f () {
    return this.x;
  }
}

Expected behavior:
TS should be able to identify x as a property of this.

Actual behavior:
Throwing:

Property 'x' does not exist on type 'A'.

Playground Link:
http://www.typescriptlang.org/play/#src=export%20default%20class%20A%20%7B%0D%0A%20%20constructor%20(%7B%20x%2C%20y%2C%20z%20%7D)%20%7B%0D%0A%20%20%20%20Object.assign(this%2C%20%7Bx%2C%20y%2C%20z%7D)%3B%0D%0A%20%20%7D%0D%0A%20%20f%20()%20%7B%0D%0A%20%20%20%20return%20this.x%3B%0D%0A%20%20%7D%0D%0A%7D

Related Issues:
no

Side Note:
I am using TS with Javascript because YouCompleteMe switched to using TSServer for semantic completion. I absolutely love TS so was really happy about the switch! Thanks for the great work!

Inizia con la riproduzione collegata in TypeScript Playground ed esamina come viene verificato Object.assign(this, {x, y, z}) nel costruttore della classe. Determina il comportamento atteso del controllo dei tipi per this.x e aggiungi un test di regressione; il lavoro è completato quando l’errore di proprietà segnalato è risolto ed esiste una copertura per questo schema.