Cannot find module 'firebase-admin/app'

package.json requirements look like this –

  "dependencies": {
    "@sentry/node": "^5.30.0",
    "body-parser": "1.19.0",
    "express": "^4.17.1",
    "firebase-admin": "10.0.0",
    "mysql": "^2.18.1",
    "pug": "3.0.2"
  }

node_modules has the corresponding module in the path ~/node_modules/firebase-admin/lib/app

Node code reads as –

const initializeApp  = require('firebase-admin/app');

And when the app is run, the following stacktrace emerges.

 Error: Cannot find module 'firebase-admin/app'
     at Function.Module._resolveFilename (module.js:547:15)
     at Function.Module._load (module.js:474:25)
     at Module.require (module.js:596:17)
     at require (internal/module.js:11:18)
     at Object.<anonymous> (/var/www/html/project/backend/main.js:16:24)
     at Module._compile (module.js:652:30)
     at Object.Module._extensions..js (module.js:663:10)
     at Module.load (module.js:565:32)
     at tryModuleLoad (module.js:505:12)
     at Function.Module._load (module.js:497:3)

[shalomhalbert]

Solved it by ignoring the import recommendation. Instead of

'use strict';

const { initializeApp } = require('firebase-admin/app');
const { getFirestore, Timestamp, GeoPoint } = require('firebase-admin/firestore');

exports.initializeApp = () => initializeApp();
exports.getFirestore = () => getFirestore();
exports.Timestamp = Timestamp;
exports.GeoPoint = GeoPoint;

I am now using what existed before v10:

'use strict';

const firebaseAdmin = require('firebase-admin');

exports.initializeApp = () => firebaseAdmin.initializeApp();
exports.getFirestore = () => firebaseAdmin.firestore();
exports.Timestamp = firebaseAdmin.firestore.Timestamp;
exports.GeoPoint = firebaseAdmin.firestore.GeoPoint;

[HelderSi]

I started to use firebase-admin@^10.0.1 and I had this error when running jest tests. It couldn’t map “firebase-admin/app” to “firebase-admin/lib/app” as expected. So I have mapped this manually on jest.config.ts:

import { pathsToModuleNameMapper } from 'ts-jest/utils';
import { compilerOptions } from './tsconfig.json';

...
export default {
 ...
 moduleNameMapper: pathsToModuleNameMapper(
    {
      ...compilerOptions.paths,
      'firebase-admin/*': ['node_modules/firebase-admin/lib/*'],
    },
    {
      prefix: '<rootDir>',
    },
  ),
...
}

That worked for me.

And just to note, my tsconfig.json is like this:

{
  "compilerOptions": {
    ...
    "baseUrl": ".",
    "paths": {
      "modules/*": [
        "src/modules/*"
      ],
      "shared/*": [
        "src/shared/*"
      ],
    }
  }
}