firebase-admin-node: Jest testing failing with new import entry points

Enviornment

• Operating System version: Mac OS 11.6
• Firebase SDK version: 10.0.0
• Firebase Product: auth, firestore, (probably all)
• Node.js version: 16.0.0
• NPM version: 8.0.0

Unable to use new imports with Jest for testing

Unable to use new imports with Jest for testing. When using Jest on a very, very simple project we get one error. On a more complex project, ESM errors start arriving.

I’m pretty sure all this is around Babel and how it is not grabbing the correct setup around how this lib exposed the experimental ESM syntax.

###- Problem One

Jest fails on a very simple project.

Error

 FAIL  src/example.test.ts
  ● Test suite failed to run

    Cannot find module 'firebase-admin/app' from 'src/example.ts'

    Require stack:
      src/example.ts
      src/example.test.ts

    > 1 | import { initializeApp, applicationDefault, App } from 'firebase-admin/app';
        | ^
      2 | import {
      3 |   getFirestore,
      4 |   Firestore,

      at Resolver.resolveModule (node_modules/jest-resolve/build/resolver.js:322:11)
      at Object.<anonymous> (src/example.ts:1:1)

Test Suites: 1 failed, 1 total
Tests:       0 total
Snapshots:   0 total
Time:        2.489 s

Steps to reproduce:

Created a new project. Steps VERY basic:

mkdir fail-example
cd fail-example
npm init -y
npx tsc --init
npm i -D jest ts-jest @types/jest
npm i firebase-admin

I’ve created a function:

import { initializeApp, applicationDefault, App } from 'firebase-admin/app';

export const getFirebaseApp = (): App => {
  const app = initializeApp({
    credential: applicationDefault(),
  });
  return app;
};

And the Jest test:

import { getFirebaseApp } from './example';

describe('Testing firebase-admin imports', () => {
  it('Should import a firebase instance without a problem', () => {
    const result = getFirebaseApp();
    expect(result).toBeDefined();
  });
});

###- Problem Two

I have a MUCH more complex project using nrwl/nx for mono-repo support. My tsconfig files and overall config are more complex. This starts to fail around ES Modules

error

 FAIL   server-database  libs/server/database/src/lib/firebase.spec.ts
  ● Test suite failed to run

    Jest encountered an unexpected token

    Jest failed to parse a file. This happens e.g. when your code or its dependencies use non-standard JavaScript syntax, or when Jest is not configured to support such syntax.

    Out of the box Jest supports Babel, which will be used to transform your files into valid JS based on your Babel configuration.

    By default "node_modules" folder is ignored by transformers.

    Here's what you can do:
     • If you are trying to use ECMAScript Modules, see https://jestjs.io/docs/ecmascript-modules for how to enable it.
     • If you are trying to use TypeScript, see https://jestjs.io/docs/getting-started#using-typescript
     • To have some of your "node_modules" files transformed, you can specify a custom "transformIgnorePatterns" in your config.
     • If you need a custom transformation specify a "transform" option in your config.
     • If you simply want to mock your non-JS modules (e.g. binary assets) you can stub them out with the "moduleNameMapper" config option.

    You'll find more details and examples of these config options in the docs:
    https://jestjs.io/docs/configuration
    For information about custom transformations, see:
    https://jestjs.io/docs/code-transformation

    Details:

    /Users/brian/Development/yet-another-project/graphql-core/node_modules/firebase-admin/lib/auth/index.d.ts:22
    import { App } from '../app/index';
    ^^^^^^

    SyntaxError: Cannot use import statement outside a module