The Firebase Remote Config Web quickstart app demonstrates using Remote Config to define user-facing text in a web app.

This is a simple example of using Remote Config to override in-app default values by defining server-side parameter values in the Firebase console. This example demonstrates a small subset of the capilities of Firebase Remote Config. To learn more about how you can use Firebase Remote Config in your app, see the Firebase Remote Config introduction.

1. Follow step 1 and 2 here to register a web app with your Firebase project. Copy your Firebase config object (from the "Add Firebase to your web app" dialog), and paste it in the config.ts file in the remote-config directory.
2. Set up Remote Config for your Firebase project:
   1. In the Firebase console, open your project
   2. Select Remote Config from the menu to view the Remote Config dashboard
   3. Define a parameter with key welcome_message and default value Hello World
   4. Click "Add parameter", and then click "Publish changes"
3. You must have the Firebase CLI installed. If you don't have it install it with npm install -g firebase-tools and then configure it with firebase login.
4. On the command line run firebase use --add and select the Firebase project you have created

To run the sample app locally during development:

1. Run npm install to install dependencies.
2. Run firebase emulators:start to start the local Firebase emulators. Note: phone authentication required ReCaptcha verification which does not work with the Firebase emulators. These examples skip connecting to the emulators.
3. Run npm run dev to serve the app locally using Vite This will start a server locally that serves index.html on http://localhost:5173/index.html.
4. Click REQUEST PERMISSION button to request permission for the app to send notifications to the browser.
5. Use the generated Instance ID token (IID Token) to send an HTTP request to FCM that delivers the message to the web application, inserting appropriate values for YOUR-SERVER-KEY and YOUR-IID-TOKEN.
6. Change the parameter value in the Firebase Console (the value of welcome_message), and then click "Publish changes"
7. Tap Fetch Remote Welcome in the app to fetch new parameter values and see the resulting change in the app.

Running the app using the Firebase CLI:

1. Run npm install to install dependencies.
2. Run npm run build to build the app using Vite.
3. Run firebase emulators:start to start the local Firebase emulators. Note: phone authentication required ReCaptcha verification which does not work with the Firebase emulators. These examples skip connecting to the emulators.
4. In your terminal output, you will see the "Hosting" URL. By default, it will be 127.0.0.1:5002, though it may be different for you.
5. Navigate in your browser to the URL output by the firebase emulators:start command.
6. Click REQUEST PERMISSION button to request permission for the app to send notifications to the browser.
7. Use the generated Instance ID token (IID Token) to send an HTTP request to FCM that delivers the message to the web application, inserting appropriate values for YOUR-SERVER-KEY and YOUR-IID-TOKEN.
8. Change the parameter value in the Firebase Console (the value of welcome_message), and then click "Publish changes"
9. Tap Fetch Remote Welcome in the app to fetch new parameter values and see the resulting change in the app.

To deploy the sample app to production:

1. Run firebase deploy. This will deploy the sample app to https://<project_id>.firebaseapp.com.

This section provides some additional information about how the quickstart example sets in-app default parameter values and fetches values from the Remote Config service

In-app default values are set using a JSON object using the setDefaults method. Then, you can override only those values that you need to change from the Firebase console or the REST API. This lets you use Remote Config for any default value that you might want to override in the future, without the need to set all of those values in the Firebase console.

When an app calls fetch, locally stored parameter values are used unless the minimum fetch interval is reached. The minimal fetch interval is determined by:

1. The parameter passed to fetch(long minFetchInterval).
2. The minimum fetch interval set in Remote Config settings.
3. The default minimum fetch interval, 12 hours.

Fetched values are immediately activated when retrieved using fetchAndActivate. In the quickstart sample app, you call fetchAndActivate from the UI by tapping Fetch Remote Welcome.

To control when fetched values are activated and available to your app use fetch. The values are locally stored, but not immediately activated. To activate fetched values so that they take effect, call the activate method.

You can also create a Remote Config Setting to enable "developer mode". By using a small (even 0) value for minimumFetchIntervalInSeconds, you can make many more requests per hour, so you can test your app with different Remote Config parameter values during development.

• To learn more about fetching data from remote config, see Firebase Remote Config loading strategies.
• To learn about parameters and conditions that you can use to change the behavior and appearance of your app for segments of your userbase, see Remote Config Parameters and Conditions.

• Stack Overflow
• Firebase Support

Copyright 2019 Google, Inc.

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