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!

Commencez par examiner la reproduction TypeScript Playground liée et étudiez comment Object.assign(this, {x, y, z}) est vérifié dans le constructeur de la classe. Déterminez le comportement attendu de la vérification de type pour this.x et ajoutez un test de régression ; le travail est terminé lorsque l’erreur de propriété signalée est résolue et qu’une couverture existe pour ce modèle.