bulk upload json data to firestore

upload-json.js

const admin = require('./node_modules/firebase-admin');
const collectionKey = 'ExampleCollection'; /* 1. The name of your collection here, case-sensitive. */
const data = require('./data.json'); /* 2. A path to your data in JSON format here. */

admin.initializeApp({
  credential: admin.credential.cert({
      /* 3. Your ServiceAccount details here. */
      'type': 'service_account',
      'project_id': '...',
      'private_key_id': '...',
      'private_key': '...',
      'client_email': '...',
      'client_id': '...',
      'auth_uri': 'https://accounts.google.com/o/oauth2/auth',
      'token_uri': 'https://oauth2.googleapis.com/token',
      'auth_provider_x509_cert_url': 'https://www.googleapis.com/oauth2/v1/certs',
      'client_x509_cert_url': '...'
  }),
  databaseURL: '', /* 4. Your database URL here. */
});

const firestore = admin.firestore();
const settings = { timestampsInSnapshots: true };

firestore.settings(settings);

if (data && (typeof data === 'object')) {
  Object.keys(data).forEach(docKey => {
    firestore.collection(collectionKey).doc(docKey).set(data[docKey]).then((res) => {
        console.log('Document ' + docKey + ' successfully written!');
    }).catch((error) => console.error('Error writing document: ', error));
  });
}