Supported environments for the Firebase JavaScript SDK

Supported environments

The Firebase JavaScript SDK is officially supported in the following environments.

Browsers

Other environments

Polyfills

The Firebase JavaScript SDK is built on the latest standards of the web platform. Some older browsers and JavaScript environments do not support all the features required by Firebase. If you must support these browsers/environments, then you need to load polyfills accordingly.

The sections below identify most of the polyfills you might need.

Required polyfills

Optional polyfills

Suggested polyfills

Required Polyfill Setup for React Native and Expo

For React Native and Expo if you are uploading a base-64 encoded string, you need to do the following:

Install base-64 from npm:

npm install base-64

Import decode from base-64 and attach it to the global scope as atob so Cloud Storage can access it.

import { decode } from 'base-64';

if(typeof atob === 'undefined') {
  global.atob = decode;
}

Add polyfills in your application

Option 1: (Recommended) Use bundler integrated with Babel

If you're using a bundler, integrate with Babel and @babel/preset-env to get polyfills.

Use Babel's interactive setup guide to learn how to integrate Babel with your bundler.

With Babel, you don't need to worry about the exact polyfills to include. Instead, you specify the minimal browser environments that you need to support. Babel then adds the necessary polyfills for you. Babel ensures that your requirements for browser support are always met, even if Firebase or your own code starts using new ES features.

@babel/preset-env has detailed information about the available configuration options for specifying environment targets (option targets) and adding polyfills (option useBuiltIns).

Option 2: (Not Recommended) Add polyfills manually

You can add polyfills manually using your favorite polyfill libraries (for example, core-js).

import 'core-js/stable'
import 'cross-fetch/polyfill';

core-js also provides an all-in-one polyfill file that you can directly include in the HTML page.

This option can be a convenient way for managing polyfills if you don't use Babel. However, we don't recommend this all-in-one option for production apps as it will likely include unnecessary polyfills, which increases the page weight and hence the page load time.