How to include the document id in Firestore collection in Angular 5

Question

I have this function that gets all the posts and I want to get the id of the post any idea how to get the id of the post or How to include the id when I add the document to the collection

get_the_posts(){
    this.Post_collection = this.afs.collection('posts'); 
    return this.Posts = this.Post_collection.valueChanges();
}

That gives me this output:

[
   { name: 'post 1 name' description: 'post description'}, 
   { name: 'post 2 name' description: 'post description'},
   { name: 'post 3 name' description: 'post description'},
]

And i want this output

[
   { id: 'm9mggfJtClLCvqeQ', name: 'post 1 name' description: 'post description'}, 
   { id: 'm9mggfJtCldsadaf', name: 'post 2 name' description: 'post description'},
   { id: 'm9mggfJtCdsasavq', name: 'post 3 name' description: 'post description'},
]

Answer 1

.valueChanges() returns only data without any meta data. you can use .snapshotChanges() for that

this.Post_collection = this.afs.collection('posts');
return this.Posts = this.Post_collection.snapshotChanges().map(actions => {
  return actions.map(a => {
    const data = a.payload.doc.data();
    const id = a.payload.doc.id;
    return { id, ...data };
  });
});

also import import { Observable } from 'rxjs/Observable';

For your second question how to add id when pushing data to firestore. try

//get id from firestore
    let id = this.afs.createId();

    this.post = {
      id:id,
      name:'name',
      description:'description'
    }

    this.afs.collection('posts').doc(id).set(this.post).then();

Now you can use .valueChanges() to get the data.