Copy from one firestore collection to another

copy-firestore-collection.mjs

import admin from "firebase-admin";
import fs from "fs/promises";

const serviceAccount1 = JSON.parse(await fs.readFile("./service-account-1.json"));
const serviceAccount2 = JSON.parse(await fs.readFile("./service-account-2.json"));

const admin1 = admin.initializeApp({ credential: admin.credential.cert(serviceAccount1) }, "one");
const admin2 = admin.initializeApp({ credential: admin.credential.cert(serviceAccount2) }, "two");

const db1 = admin1.firestore();
const db2 = admin2.firestore();

const snapshot = await db1.collection("collectionName").get();
const jsonData = snapshot.docs.map((doc) => doc.data());

const batch2 = db2.batch();
jsonData.forEach((data) => {
  const ref = db2.collection("storyKeywords").doc(data.id);
  batch2.set(ref, data);
});
await batch2.commit();