Good Morning,
I tried adding a new created object from this class:
export class Sponsor implements ISponsor { title: string; description?: s
Firestore does not support that. But you can use https://github.com/typestack/class-transformer It works perfectly fine for us.
You can also use Object.assign({}, sponsor)
so in yor case it would be
this.collection.doc(sponsor.id).set(Object.assign({}, sponsor));