`const admin = require('firebase-admin')` crashes with `TypeError: Cannot read properties of undefined (reading 'env')`

[dlcole]

Earlier this week I, like others, started receiving web pack errors such as

Module not found: Error: Can't resolve 'util' in '/Users/david/Documents/NativeScriptProjects/rrr/node_modules/@fastify/busboy/lib/utils'

BREAKING CHANGE: webpack < 5 used to include polyfills for node.js core modules by default.
This is no longer the case. Verify if you need this module and configure a polyfill for it.

If you want to include a polyfill, you need to:
    - add a fallback 'resolve.fallback: { "util": require.resolve("util/") }'
    - install 'util'
If you don't want to include a polyfill, you can use an empty module like this:
    resolve.fallback: { "util": false }

I had over 200 such errors. After investigating for several hours, I edited my webpack.config.js file thusly:

const webpack = require("@nativescript/webpack");

module.exports = (env) => {

  // See https://stackoverflow.com/questions/70428159/nativescript-8-1-migration-adding-external-to-webpack-config-js
  env.appComponents = (env.appComponents || []).concat(['./foreground-service.android'])

  webpack.init(env);

    // Learn how to customize:
    // https://docs.nativescript.org/webpack

  webpack.Utils.addCopyRule('data/**')
  webpack.Utils.addCopyRule('files/**')
  webpack.Utils.addCopyRule('**/*.db')

  webpack.mergeWebpack({
    resolve: {
      fallback: {
        assert: require.resolve("assert/"),
        browserify: false,
        buffer: require.resolve("buffer/"),
        child_process: false, 
        crypto: require.resolve("crypto-browserify"), 
        dns: false,
        fs: false,
        http: require.resolve("stream-http"),
        https: require.resolve("https-browserify"),
        http2: false,
        net: false,
        os: require.resolve("os-browserify/browser"),
        path: require.resolve("path-browserify"),
        querystring: require.resolve("querystring-es3"),
        request: false,
        stream: require.resolve("stream-browserify"),
        tls: false,
        tty: require.resolve("tty-browserify"),
        url: require.resolve("url/"),
        util: require.resolve("util/"),
        zlib: require.resolve("browserify-zlib"),
      },
    },
  });

    return webpack.resolveConfig();
};

In short, I installed the packages suggested by the log file errors, such as util, and added the associated require.resolve, and set to false those items that did not have a suggested package. This resolved the build errors, but now I get a crash when I navigate to a page that requires firebase-admin (so as to send firebase messages):

  System.err: An uncaught Exception occurred on "main" thread.
  System.err: Calling js method onClick failed
  System.err: TypeError: Cannot read properties of undefined (reading 'env')
  System.err:
  System.err: StackTrace:
  System.err: ./node_modules/util/util.js(file: app/webpack:/rrr/node_modules/util/util.js:109:11)
  System.err:   at __webpack_require__(file: app/webpack:/rrr/webpack/bootstrap:24:0)

I have to think these two are related, but I’m at a loss as to how to proceed. Can anyone confirm whether this is the correct approach to handling the webpack 5 polyfill errors?

[edusperoni]

Most likely you need to polyfill global.process as it's undefined in NativeScript, and these libraries check for process.env.

That said, I'd strongly recommend against using firebase-admin in your app. From the package documentation:

Please also note that the Admin SDK should only be used in server-side/back-end environments controlled by the app developer. This includes most server and serverless platforms (both on-premise and in the cloud). It is not recommended to use the Admin SDK in client-side environments.

Using it in your app is most likely result in your firebase credentials leaking and being abused, as opening up APKs and IPAs is trivial.

[dlcole]

@edusperoni The only reason I was using firebase-admin is because that's the only example I saw in the @firebase-messaging doc. Should I be posting hhtp requests like I did with the older firebase plugin, but using the newer firebase API?

[edusperoni]

@dlcole the examples there are for the backend to send messages. In which case you need to have a backend with your credentials and expose an API that the user will call which in turn calls the admin SDK to post a message.

You'd usually need firebase messaging if you need to send messages to specific users (chat app, user send message to another user, you trigger a firebase message with the data), send messages independent of user action (ad campaign, etc), and similar things. If you need to display local notifications instantly or after a while you can use the local-notifications plugin