set_with_merge.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 set_with_merge_modular]
import { doc, setDoc } from "firebase/firestore"; 

const cityRef = doc(db, 'cities', 'BJ');
await setDoc(cityRef, { capital: true }, { merge: true });
// [END set_with_merge_modular]