Firebase Essentials: Firestore Database Write with JavaScrip

Activate Cloud Shell

Cloud Shell is a virtual machine that is loaded with development tools. It offers a persistent 5GB home directory and runs on the Google Cloud. Cloud Shell provides command-line access to your Google Cloud resources.

Click Activate Cloud Shell

at the top of the Google Cloud console.

When you are connected, you are already authenticated, and the project is set to your PROJECT_ID. The output contains a line that declares the PROJECT_ID for this session:

Your Cloud Platform project in this session is set to YOUR_PROJECT_ID

gcloud is the command-line tool for Google Cloud. It comes pre-installed on Cloud Shell and supports tab-completion.

(Optional) You can list the active account name with this command:

gcloud auth list

Copied!

Click Authorize.
Your output should now look like this:

Output:

ACTIVE: *
ACCOUNT: student-01-xxxxxxxxxxxx@qwiklabs.net

To set the active account, run:
    $ gcloud config set account `ACCOUNT`

(Optional) You can list the project ID with this command:

gcloud config list project

Copied!

Output:

[core]
project = <project_ID>

Example output:

[core]
project = qwiklabs-gcp-44776a13dea667a6

Note: For full documentation of gcloud, in Google Cloud, refer to the gcloud CLI overview guide.

Overview

This lab guides you through creating a Firebase Firestore database and writing data to it using a JavaScript application. You'll learn how to initialize Firebase, structure your data, and use the Firebase CLI for authentication. This eliminates the need for a custom service account.

Task 1. Adding a Firebase Project to Google Cloud

Attach a new Firebase project to your Google Cloud proiect by visting the Firebase console.

Go to the Firebase Console.
```
https://console.firebase.google.com/
```
Copied!

Note:
Navigate to the Firebase Console in your browser.
Click Create a Firebase Project and follow the instructions to create a new project.

Note:
On the Create a project page, scroll down to the bottom of the screen and click Add Firebase to Google Cloud Project.
On the following screen, enter the Google Cloud project identifier shown below.
```
qwiklabs-gcp-01-d7976e499e7a
```
Copied!

Note:
This project identifier is linked to a Google Cloud project. Accept the Firebase terms and conditions to create the Firebase project.
Follow the remaining instructions to create a new Firebase project.

Note:
Firebase includes options for billing and analytics. These options are not used in this lab, so accept the default options to complete the creation of the Firebase project.

Task 2. Set Up Your Environment

Return to Google Cloud and use CloudShell to configure your Google Cloud project and initialize Firebase.

Set your project ID.
```
gcloud config set project qwiklabs-gcp-01-d7976e499e7a
```
Copied!

Note:
This command sets your active project.
Set your default region.
```
gcloud config set run/region us-east1
```
Copied!

Note:
This command sets your active region.
Set your default zone.
```
gcloud config set compute/zone us-east1-c
```
Copied!

Note:
This command sets your active zone.

Enable the necessary APIs.

gcloud services enable compute.googleapis.com container.googleapis.com iap.googleapis.com firebase.googleapis.com firebaseextensions.googleapis.com eventarc.googleapis.com pubsub.googleapis.com storage.googleapis.com run.googleapis.com

Copied!

Note:
This command enables the Google APIs required for this lab.

Create a Firestore database in Native mode.
```
gcloud firestore databases create --location=nam5 --database='(default)'
```
Copied!

Note:
This command provisions a Firestore database in the nam5 (North America) multi-region. The database must exist before you can deploy or run code that interacts with it. You can choose a different region if needed.

Task 3. Configure the Firebase Environment

Enable the Firebase environment to use for development.

Install the Firebase CLI.
```
npm install -g firebase-tools
```
Copied!

Note:
This command installs the Firebase CLI globally.
Create a new directory for the project.
```
mkdir firestore-app && cd firestore-app
```
Copied!

Note:
This command creates a folder for the lab content. This folder will contain the code and configurations generated during the lab.
Log in to Firebase using the CLI:
```
firebase login --no-localhost
```
Copied!

Note:
This command authenticates the Firebase CLI with your Google account.
Initialize Firebase in your project directory.
```
firebase init
```
Copied!

Note:
This command initializes a Firebase project in the current directory.
When prompted:
- Select Firestore and Functions.
- For Firestore, accept the default location.
- For Functions, choose JavaScript and decline ESLint.

Task 4. Write Data to Firestore

Now, write some data to your Firestore database using JavaScript. For convienience a Firebase Cloud Function will be used to populate the Firestore database.

Replace functions/index.js file with the following code:

// functions/index.js
const {initializeApp} = require("firebase-admin/app");
const {getFirestore} = require("firebase-admin/firestore");

// Import onRequest instead of onCall
const {onRequest} = require("firebase-functions/v2/https");
const {setGlobalOptions} = require("firebase-functions/v2");

initializeApp();

setGlobalOptions({ region: 'us-east1' });

// Use onRequest for a standard HTTP endpoint
exports.addMessage = onRequest(async (req, res) => {
  // Check that the request method is POST
  if (req.method !== 'POST') {
    res.status(405).send({ error: 'Method Not Allowed! Please use POST.' });
    return;
  }

  // Get the text from the request body directly.
  // The {"data": ...} wrapper is not needed for onRequest functions.
  const text = req.body.text;

  // Validate the input and send back a standard HTTP error response
  if (!text || text.length > 200) {
    res.status(400).send({
      error: 'The message text is either missing or too long (max 200 characters).',
    });
    return;
  }

  try {
    const writeResult = await getFirestore()
      .collection('messages')
      .add({ original: text });

    console.log(`Message with ID: ${writeResult.id} added.`);

    // Send a success response
    res.status(200).send({ message: `Message with ID: ${writeResult.id} added to Firestore.` });
  } catch (error) {
    console.error("Error writing to Firestore:", error);
    res.status(500).send({ error: 'An internal error occurred.' });
  }
});

Copied!

Note:
This code defines a Firebase Function that writes a message to the messages collection in Firestore. It uses the Firebase Admin SDK, which leverages the Firebase CLI's authentication for simplified access.

Replace the functions/package.json file with the following configuration to set the correct JavaScript engine and add the required dependencies.

{
  "name": "functions",
  "scripts": {
    "lint": "eslint .",
    "serve": "firebase emulators:start --only functions",
    "shell": "firebase functions:shell",
    "start": "npm run shell",
    "deploy": "firebase deploy --only functions",
    "logs": "firebase functions:log"
  },
  "engines": {
    "node": "22"
  },
  "main": "index.js",
  "dependencies": {
    "firebase-admin": "^11.8.0",
    "firebase-functions": "^4.6.0"
  },
  "devDependencies": {
    "@firebase/rules-unit-testing": "^2.0.2",
    "eslint": "^8.15.0",
    "eslint-config-google": "^0.14.0",
    "firebase-functions-test": "^3.0.0"
  },
  "private": true
}

Copied!

Note:
Ensure the engines/node field is set to v22, the firebase-admin dependency is included, and firebase-functions is v4.6.0 or later.

Install the dependencies.
```
cd functions && npm install
```
Copied!

Note:
This command installs all the necessary packages defined in your package.json file.
Return to the Firebase application folder.
```
cd ~/firestore-app
```
Copied!

Note:
This command returns to the parent folder, ready for deployment.
Deploy the function to Firebase.
```
firebase deploy --only functions
```
Copied!

Note:
This command deploys your Firebase Function to the cloud.

If you see an error relating to "There was an issue deploying your functions. Verify that your project has a Google App Engine instance setup at https://console.cloud.google.com/appengine and try again." This indicates a background processes have not completed.

Please wait a couple of minutes before trying the deploy command again.

Task 5. Test the Function

Verify that your Firebase Cloud Function is writing data to Firestore correctly.

List the available Firebase Cloud Functions.

firebase functions:list

Copied!

Note:
This command lists the available Firebase Functions for the active project.

EXPECTED OUTPUT

┌────────────┬─────────┬─────────┬─────────────┬────────┬──────────┐
│ Function   │ Version │ Trigger │ Location    │ Memory │ Runtime  │
├────────────┼─────────┼─────────┼─────────────┼────────┼──────────┤
│ addMessage │ v2      │ https   │ us-east1 │ 256    │ nodejs22 │
└────────────┴─────────┴─────────┴─────────────┴────────┴──────────┘

Get the URI for the Firebase Cloud Function.
```
FUNCTION_URI=$(gcloud functions describe addMessage --region us-east1 --format=json | jq -r .serviceConfig.uri)
```
Copied!

Note:
This command retrieves the addMessage function object and extracts the URI.

Call the Firebase Cloud Function using curl.

MESSAGE_TEXT="Hello from the CLI!"
curl -X POST "\(FUNCTION_URI" -H "Content-Type: application/json" -d '{"text":"'"\)MESSAGE_TEXT"'"}'

Copied!

Note:
This command invokes the addMessage function with the provided data. The function name is case-sensitive.

{"message":"Message with ID: 9GMxSOZp0yynY0I57Dav added to Firestore."}

Check the Firestore console to confirm the data has been written.

Open the Firebase console for your project. Navigate to Firestore Database, and you should see a new document in the 'messages' collection.

Note:
Verify that the data has been written to Firestore.

Solution of Lab

💡

No need to do anything, please wait about 5 minutes, and the lab will do it automatically.

Firebase Essentials: Firestore Database Write with JavaScript - gem-firebase-firestore-write-javascript

Comments

Tip & Tricks

Knowledge Catalog: Qwik Start - Command Line - GSP1144

More from this blog

Daily Tech Brief — 10/08/2026

Daily Tech Brief — 09/08/2026

Daily Tech Brief — 08/08/2026

Daily Tech Brief — 07/08/2026

Knowledge Catalog: Qwik Start - Command Line - GSP1144

Activate Cloud Shell

Overview

Task 1. Adding a Firebase Project to Google Cloud

Task 2. Set Up Your Environment

Task 3. Configure the Firebase Environment

Task 4. Write Data to Firestore

Task 5. Test the Function

Solution of Lab

Command Palette

Comments

Tip & Tricks

Knowledge Catalog: Qwik Start - Command Line - GSP1144

More from this blog

Activate Cloud Shell

Overview

Task 1. Adding a Firebase Project to Google Cloud

Task 2. Set Up Your Environment

Task 3. Configure the Firebase Environment

Task 4. Write Data to Firestore

Task 5. Test the Function

Solution of Lab