firebase firestore add to array code example

Example 1: firestore set a document

let data = {
  name: 'Los Angeles',
  state: 'CA',
  country: 'USA'
};

// Add a new document in collection "cities" with ID 'LA'
let setDoc = db.collection('cities').doc('LA').set(data);

Example 2: firestore update array

let washingtonRef = db.collection('cities').doc('DC');

// Atomically add a new region to the "regions" array field.
let arrUnion = washingtonRef.update({
  regions: admin.firestore.FieldValue.arrayUnion('greater_virginia')
});
// Atomically remove a region from the "regions" array field.
let arrRm = washingtonRef.update({
  regions: admin.firestore.FieldValue.arrayRemove('east_coast')
});

Example 3: document.set() firebasefirestore java

// Create an initial document to update.var frankDocRef = db.collection("users").doc("frank");frankDocRef.set({    name: "Frank",    favorites: { food: "Pizza", color: "Blue", subject: "recess" },    age: 12});// To update age and favorite color:db.collection("users").doc("frank").update({    "age": 13,    "favorites.color": "Red"});