How to get particular document data with id ? | AngularFire 5.1.1 | Cloud Firestore | Documents

Question

I am using Data access service to get the data from firebase firestore.

How to use snapshotChanges()method for getting particular document data with id

getProduct(id: number): Observable<Product> {
    this.productsDocuments = this.angularfirestore.doc<Product>('products/' + id);
    this.product = this.productsDocuments.snapshotChanges().pipe(
      map(changes => changes.map(a => {
        const data = a.payload.doc.data() as Product;
        const id = a.payload.doc.id;
        return { id, ...data };
      }))
    );
    return this.product

I want this.product returns the document value and document id

Thank You!!

The return of `this.product` will include the id. So `this.product.id` is the id of the document. To acces it with the return you have to use `this.service.getProduct().subscribe((product) => { console.log(product.id) })` — Swoox, Jan 07 '19 at 08:25
@Swoox - Thank you for your reply your approach will work, but snapshotChanges() not work, the error Property 'map' does not exist on type 'Action>'. — Dinesh Kannan, Jan 07 '19 at 08:35

score 16 · Accepted Answer · edited Nov 19 '21 at 08:51

A document is simply an object {[field]: value} and a collection is a container for documents [document].

You are trying to get a single document/object and the problem is that you cannot map to it directly. I think that you want to get the entire collection, and then map over all of the documents.

getProduct(id: number): Observable<Product> {
    const productsDocuments = this.db.doc<Product>('products/' + id);
    return productsDocuments.snapshotChanges()
      .pipe(
        map(changes => {
          const data = changes.payload.data();
          const id = changes.payload.id;
          return { id, ...data };
        }))
  }

for a collection

getProduct(id: string): Observable<Product[]> {
    const productsDocuments = this.db.collection<Product[]>('products');
    return productsDocuments.snapshotChanges()
      .pipe(
        map(changes => changes.map(({ payload: { doc } }) => {
          const data = doc.data();
          const id = doc.id
          return { id, ...data };
        })),
        map((products) => products.find(doc => doc.id === id)))
  }

How to get particular document data with id ? | AngularFire 5.1.1 | Cloud Firestore | Documents

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