CODEWITHSUNDEEP
javascriptfirebasegoogle-cloud-firestore
randomUser786
randomUser786

Reputation: 1655

How to retrieve an element from an array that is inside an object in Firestore?

Here is the structure of my Firestore DB: structure

I have multiple arrays in the object "reserved items". Each array has more than one element stored in there. How do I retrieve the "returnDate" element from each/every single array that is in the object?

Upvotes: 1

Views: 298

Answers (2)

Renaud Tarnec
Renaud Tarnec

Reputation: 83068

reserved_items is a field of type Array, and each element of this Array is a map/JS Object. You therefore have to iterate over the JavaScript Array representing this field and use the dot notation. Here is an example with the forEach() method:

  var docRef = db.collection('...').doc('63ufq....');

  docRef
    .get()
    .then((doc) => {
      if (doc.exists) {
        const reserved_items = doc.get('reserved_items');

        reserved_items.forEach(element => console.log(element.returnDate));

      } else {
        // doc.data() will be undefined in this case
        console.log('No such document!');
      }
    })
    .catch((error) => {
      console.log('Error getting document:', error);
    });

Upvotes: 1

felixjiricka
felixjiricka

Reputation: 78

First, load your document from your firestore.

var docRef = db.collection("cities").doc("SF");

docRef.get().then((doc) => {
    if (doc.exists) {
        console.log("Document data:", doc.data());
    } else {
        // doc.data() will be undefined in this case
        console.log("No such document!");
    }
}).catch((error) => {
    console.log("Error getting document:", error);
});

now, in doc.data() is your object, which has the 'reserved_items' as property. Then you can use the map() function to iterate your 'reserved_items' and store the needed data in a variable

Upvotes: 0

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