update_document_array.js

// This snippet file was generated by processing the source file:
// ./firestore-next/test.firestore.js
//
// To update the snippets in this file, edit the source and then run
// 'npm run snippets'.

// [START update_document_array_modular]
import { doc, updateDoc, arrayUnion, arrayRemove } from "firebase/firestore";

const washingtonRef = doc(db, "cities", "DC");

// Atomically add a new region to the "regions" array field.
await updateDoc(washingtonRef, {
    regions: arrayUnion("greater_virginia")
});

// Atomically remove a region from the "regions" array field.
await updateDoc(washingtonRef, {
    regions: arrayRemove("east_coast")
});
// [END update_document_array_modular]