firebase.config.js

import admin from 'firebase-admin';

const secret = {
  type: 'service_account',
  project_id: process.env.FIREBASE_PROJECT_ID,
  private_key_id: process.env.FIREBASE_PRIVATE_KEY_ID,
  private_key: process.env.FIREBASE_PRIVATE_KEY,
  client_email: process.env.FIREBASE_CLIENT_EMAIL,
  client_id: process.env.FIREBASE_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: process.env.FIREBASE_CERT_URL,
};

if (!admin.apps.length) {
  try {
    admin.initializeApp({
      credential: admin.credential.cert(secret),
    });
  } catch (error) {
    console.log('Firebase admin initialization error', error.stack);
  }
}

export default admin.firestore();