😅 NOTE: I'm Spanish speaking and my English is pretty bad, I promise to correctly rewrite the documentation so everyone can understand it. I'm sorry.

Google Realtime App

We need to do the following actions:

Add values to a Google Sheet
Push these values automaticaly to a Firebase Realtime Database
Observe the database and show the data in the frontend every time the Google Sheet data changes.

Google Sheets (CMS) > Google Apps Script (Service) > G Suite Hub (Autom.) >Firebase Database (DB) > Angular (Front)

Setup front and firebase hosting project

Open terminal and create a new Angular project ng new <project>
Go to your project folder cd <project>
Create a new project in Firebase Console »
Install Firebase CLI » with npm install -g firebase-tools
In your terminal, login into firebase firebase login (complete the auth process)
Init firebase project firebase init
Select (*) Hosting (select with space then press enter)
Select [don't setup a default project] (selected by default)
Select public folder (selected by default)
DON'T configure as a single-page app (selected by default)
Edit .firebaserc and paste the following code

{
  "projects": {
    "default": "<your-project-id>"
  }
}

Type firebase list and copy the project id of your project recently created then replace it in .firebaserc
Edit angular.json file and replace outputPath: dist/<project> with "outputPath": "public"
Edit .gitignore file and ignore the /public folder
We need to build the frontend then type npm run build
Make a deploy to firebase hosting with firebase deploy
Open your app browser and go to https://your-project-id.firebaseapp.com/ then you can see the static frontend

💾 It is a good time for commit your changes.

Firebase Database Realtime

Go to Firebase Console » > Database and create a new Realtime Database (press next on the pop up)
In Database go to Rules tab and set read value to true then Publish the rules on the blue message

Google Sheet

Create a Google Sheet file in your Google Drive account
Open it and add some title and save (maybe <your-project>)
Then fill it with some data like this:

console	price
Playstation 4	299
Playstation 4 Pro	400
Xbox One S	299
Xbox One X	500
Nintendo Switch	299
Nintendo 2DS	140

Then in the toolbar click on Tools > Apps Script Editor (it will open a new tab)
Add some title and save, i recomend the same as google sheet title (maybe <your-project>)

We need the Apps Script ID later to clone this project with Clasp » and use ES6 features

Apps Scripts with Clasp

The Apps Scripts must be writed in JavaScript. Of course we can write our scripts in the browser, but the browser script editor only support most of ES5 features. We are in 2019 and we need to the ES6 features!

Afortunatelly, google had created Clasp ». It is an open-source tool, separate from the Apps Script platform, that lets you develop and manage Apps Script projects from your terminal rather than the Apps Script editor.

In the root folder create a new folder mkdir clasp
Then go to this folder cd clasp
Ok, open your terminal and install Clasp with npm install @google/clasp -g
Login to the Clasp CLI clasp login
Don't create a new script, we need to clone an existing project script. Open the Apps Script project (browser) created in the previous section and go to File > Project properties then copy the Apps Script ID
Back to the terminal we need to clone the project clasp clone <scriptId>
For ES6 features, we need to write our scripts with Typescript. Then change the extension of your scripts files from *.js to *.ts

We will deploy our scripts with Clasp CLI later.

💾 It is a good time for commit your changes.

Get Google Sheet data and push it to Firebase Database

Go to clasp/ folder and rename our new <script>.ts file to index.ts
Edit this and paste the following code

function writeDataToFirebase() {
  const firebaseUrl = "<firebase_url>";
  const secret = "<firebase_secret_id>";
  const base = FirebaseApp.getDatabaseByUrl(firebaseUrl, secret);

  const spreadsheetId = "<google_sheet_id>";
  const rangeName = "<tab_name>";
  const data = Sheets.Spreadsheets.Values.get(spreadsheetId, rangeName).values;

  if (!data) {
    Logger.log("No data found.");
  } else {
    Logger.log(data.parseData());
    base.setData("consoles", data.parseData());
  }
}

Array.prototype.parseData = function() {
  const [keys, ...rows] = this;
  return rows
    .filter(row => row.length)
    .map((row, i) => {
      let obj = {};
      row.forEach((item, i) => {
        obj = { ...obj, [keys[i]]: item };
      });
      return obj;
    });
};

Replace <firebase_url>, <firebase_secret_id>, <google_sheet_id>, <tab_name> with the corrects.
Now we need to push our Typescript Clasp script to Apps Script platform (browser) then type clasp push (you can use clasp push --watch to push each time you save the file)
Be careful, don't commit/push the <firebase_secret_id>
Go to our Apps Script project in the browser and see the pre-compiled code from Typescript to JavaScript
Run the script. It will fail, because we don't import FirebaseApp and Sheets API libraries.

Add Sheets API

More info: Google Sheets API v4 »

In the Apps Script editor, click Resources > Advanced Google Services.
Locate Google Sheets API in the dialog and click the corresponding toggle, setting it to on.
Click the Google API Console link.
Enter "Google Sheets API" into the search box and click on the corresponding entry in the results.
Click the Enable API button.
Return to the Apps Script editor and click the OK button on the Advanced Google Services dialog.

Add FirebaseApp API

More info: Connect Firebase to Google services »

In the script editor, click on Resources > Libraries
A popup box opens. Insert the following project key MYeP8ZEEt1ylVDxS7uyg9plDOcoke7-2l y the texbox and add the library (more info »)
Click on the box listing the different versions of the library. Select the latest public release
Click save. You can now use FirebaseApp.
Run the script again

Google needs permissions. It is OK.

At this point, you should have been able to push the Google Sheet data to Firebase Realtime Database.

💾 It is a good time for commit your changes.

"Observe" the database from Angular

Create a new component ng g c consoles
Display <app-consoles> on app.component.html
Serve the app with npm start of ng s
Install angularfire2 » with npm install firebase @angular/fire --save
Implement the following code

consoles.component.ts

Import angularfire2 and rxjs into consoles.component.ts

import { AngularFireDatabase } from "@angular/fire/database";
import { Observable } from "rxjs";

Inject AngularFireDatabase service into constructor component and implement it

export class ConsolesComponent {
  consoles: Observable<any[]>;
  constructor(db: AngularFireDatabase) {
    this.consoles = db.list("consoles").valueChanges(); // list("consoles") is the json property name in our database, same name as the column head of consoles in our Google Sheets
  }
}

More info: angularfire2 > lists

consoles.component.html

Implement the template with the async pipe

<h1>Consoles:</h1>
<ol>
  <li *ngFor="let console of (consoles | async)">
    <ul>
      <li>Console: {{ console.console }}</li>
      <li>Price: {{ console.price }}</li>
    </ul>
    <br />
  </li>
</ol>

app.module.ts

Import Firebase module and service. Import environment variables too

import { AngularFireModule } from "@angular/fire";
import { AngularFireDatabase } from "@angular/fire/database";
import { environment } from "../environments/environment"; // environment variables

Set AngularFireDatabase as a provider

providers: [AngularFireDatabase],

Set AngularFireDatabase as a provider

imports: [..., AngularFireModule.initializeApp(environment.firebase)],

More info: Remember to set your Firebase configuration in app/app.module.ts

As you can see environment.firebase is not defined, you need to edit the file environment.ts and environment.prod.ts in ./src/environments
Go to Firebase Console > Settings > Project Config. and in the Your apps section click on the </> icon, then copy the config object {...}
Paste it as a second property of environment object in both files

export const environment = {
  production: false,
  firebase: {...} // your content here
};

Ok we have to make a new build and push it to Firebase Hosting
Build the frontend with npm run build
Deploy with firebase deploy
See the result in https://your-project-id.firebaseapp.com/

💾 It is a good time for commit your changes.

Update database when edit the Google Sheet file

If we have to add new consoles to the app then go to the Google Sheet file and add a new console to the list. But we need to run the script again. Fortunately we have Project Activators in Google Apps Script editor that automates the process. Let's go there. Open the Apps Script editor of your Google Sheet

Alternativley you can go to G Suite Developer Hub » and you can see the list of all your script projects

Open the editor and click on the Project Activators button to the left of "Run" scritp

Activate the Project Activator if it wasn't activated yet

Add New Activator (bottom right button)
Select writeDataToFirebase as the function to execute
On "Event source" select Google Sheet
On "Event type" select Edit
Save and complete the auth.

Now, when you edit the Google Sheet file, the Apps Script runs and update the Firebase Realtime Database, then thanks to the RXJS Observables, we can "observe" the database changes and fetch those values whose will show in the front in real time, without reload the page.

💖 Thank you for reaching the end. I wish it had been helpful. Give the repository a star if you liked it. Keep learning!

Lucas Romero Di Benedetto

lucasromerodb/google-realtime-app

Google Realtime App

Setup front and firebase hosting project

Firebase Database Realtime

Google Sheet

Apps Scripts with Clasp

Get Google Sheet data and push it to Firebase Database

Add Sheets API

Add FirebaseApp API

"Observe" the database from Angular

consoles.component.ts

consoles.component.html

app.module.ts

Update database when edit the Google Sheet file