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!

Comienza con la reproducción vinculada en TypeScript Playground y examina cómo se comprueba Object.assign(this, {x, y, z}) en el constructor de la clase. Determina el comportamiento esperado de la comprobación de tipos para this.x y añade una prueba de regresión; se considera terminado cuando se resuelve el error de propiedad reportado y existe cobertura para este patrón.