Loads JSON data into a Firestore database (cloud or local emulator) -- command-line JavaScript/node

load_json_to_firestore.js

/**
 * load_json_to_firstore.js
 *
 * This code is a "node script" used to load data into your Firestore database, either in "the cloud" or the emulator.
 *
 * The script is a "client app", so it logs in with Firebase Auth using email/password from the variable USER1.
 *
 * The USER1 user ([email protected]) must exist in your Firebase project and have write access
 * to the collection(s) you are populating.  You can create that account via Firebase Console >> Authentication.
 *
 * To use:
 *  1. Import the 'firebase' and 'esm' NPM modules to your project (Run the command: `npm install firebase esm`)
 *  2. Edit the data for USER1 and FIREBASE_CONFIG
 *
 * To run, I added to the package.json of my project:
 *
 *  "scripts": {
 *    "load-data": "node -r esm ./load_json_to_firestore.js 2>&1 | tee load_json.log",
 *
 *
 * and then run using the command: `npm run load-data`.
 *
 * Alternatively, you could just run the script directly with:
 *    `node -r esm ./load_json_to_firestore.js`
 */

import { initializeApp } from 'firebase/app';
import {
  addDoc,
  collection,
  getFirestore,
  connectFirestoreEmulator,
} from 'firebase/firestore';
import { getAuth, signInWithEmailAndPassword } from 'firebase/auth';

const USER1 = {
  email: '[email protected]',
  password: 'xxx',
};

let FIRESTORE;
let AUTH;

const initializeFB = async () => {
  // USE YOUR FIREBASE PROJECT SETTINGS:
  //   Firebase Console >> Project Overview >> Apps
  //    >> (select or "Add App" web app) >> Config
  const firebaseConfig = {
    apiKey: 'xxx',
    appId: 'xxx',
    authDomain: 'xxx',
    databaseURL: 'xxx', // use project value for cloud, or use emulator values such as "http://192.168.1.53:5001/" (see USE_FIREBASE_EMULATOR below)
    messagingSenderId: 'xxx',
    projectId: 'xxx',
  };

  let fbApp = initializeApp(firebaseConfig);
  FIRESTORE = getFirestore(fbApp);

  let USING_FIREBASE_EMULATOR = true;
  if (USING_FIREBASE_EMULATOR) {
    // I explicitly set "host" and "port" in firebase.json so that devices
    // on my local network can access the emulator:
    //        "emulators": {
    //          "functions": {
    //            "port": 5001,
    //            "host": "192.168.1.53"
    //          },
    //          "firestore": {
    //            "port": 5002,
    //            "host": "192.168.1.53"
    //          },
    //       ...
    //
    connectFirestoreEmulator(FIRESTORE, '192.168.1.53', 5002);
  }

  try {
    AUTH = getAuth();
    await signInWithEmailAndPassword(AUTH, USER1.email, USER1.password);
    let currUser = AUTH.currentUser;
    console.log(`Logged in with USER1 uid(${currUser.uid})`);
  } catch (ex) {
    console.error(ex.message);
    throw ex;
  }
};

const loadUsers = async (collectionName, dataFile) => {
  const data = require(dataFile);
  const dataKey = 'users';
  let count = 0;

  if (
    data &&
    typeof data === 'object' &&
    data[dataKey] &&
    typeof data[dataKey] === 'object'
  ) {
    console.log(
      `${dataFile} - have ${data[dataKey].length} records to process`
    );
    for (let i = 0; i < data[dataKey].length; i++) {
      try {
        let userRecord = data[dataKey][i];
        let collRef = collection(FIRESTORE, collectionName);
        let docRef = await addDoc(collRef, userRecord);
        console.log(`NEW DOC: ${collectionName}/${docRef.id}`);
      } catch (ex) {
        console.error(`Exception on`);
      }
    }
  } else {
    console.error(`ERROR: dataFile (${dataFile})`);
    console.error(`ERROR: typeof data (${typeof data})`);
    console.error(`ERROR: typeof data[${dataKey}] - (${typeof data[dataKey]})`);
  }
};

const main = async () => {
  try {
    console.log(`${Date()} >>> Initialize Firebase`);
    await initializeFB();
    console.log(`${Date()} >>> Start Loading Users`);

    await loadUsers('users', './data/users.json'); // loads users.json into "users" collection

    console.log(`${Date()} >>> Success!`);
    process.exit(0);
  } catch(ex) {
    console.log(`${Date()} >>> EXCEPTION: ${ex.message}`);
    process.exit(1);
  }
};

main();

users.json

{
  "users": [
    {
      "firstName": "Fred",
      "lastName": "Flintstone",
      "displayName": "Freddy My Boy",
      "email": "[email protected]",
      "role": "Staff",
    },
    {
      "firstName": "Barney",
      "lastName": "Rubble",
      "displayName": "You Nitwit",
      "email": "[email protected]",
      "role": "Admin",
    }
  ]
}