Node.js -Firebase Service Account Private Key won't parse

I use .env variables in my app.js file to access the keys. Everything was working fine until I downloaded a new Firebase Service Account Private Key. When I replaced the old value with the new value I can no longer access the key because in terminal when I run node app.js I keep getting an error message:

/Users/Cpu/Desktop/...../node_modules/firebase-admin/lib/auth/credential.js:129 throw new error_1.FirebaseAppError(error_1.AppErrorCodes.INVALID_CREDENTIAL, 'Failed to parse private key: ' + error); ^

Error: Failed to parse private key: Error: Invalid PEM formatted message. at FirebaseAppError.FirebaseError [as constructor] (/Users/Cpu/Desktop/...../node_modules/firebase-admin/lib/utils/error.js:39:28) at FirebaseAppError.PrefixedFirebaseError [as constructor] (/Users/Cpu/Desktop/...../node_modules/firebase-admin/lib/utils/error.js:85:28) at new FirebaseAppError (/Users/Cpu/Desktop/...../node_modules/firebase-admin/lib/utils/error.js:119:28) at new Certificate (/Users/Cpu/Desktop/...../node_modules/firebase-admin/lib/auth/credential.js:129:19) at new CertCredential (/Users/Cpu/Desktop/...../node_modules/firebase-admin/lib/auth/credential.js:192:64) at Object.cert (/Users/Cpu/Desktop/.....) at Object. (/Users/Cpu/Desktop/...../app.js:14:32) at Module._compile (module.js:571:32) at Object.Module._extensions..js (module.js:580:10) at Module.load (module.js:488:32) at FirebaseAppError.FirebaseError [as constructor] npm ERR! code ELIFECYCLE npm ERR! errno 1

All I did was c+p the new Private Key and then added it and saved the .env file, pushed to heroku, and it's no longer working. I even downloaded a new Private Key but the same problem occurs.

The old and new Private Keys

// old Private Key
-----BEGIN PRIVATE KEY-----\nbbbbbbbb\n-----END PRIVATE KEY-----\n

// new Private Key
-----BEGIN PRIVATE KEY-----\nzzzzzzzz\n-----END PRIVATE KEY-----\n

The .env file:

FIREBASE_PROJECT_ID=wwwwwwww
FIREBASE_CLIENT_EMAIL=xxxxxxxx
FIREBASE_DATABASE_URL=yyyyyyyy
FIREBASE_PRIVATE_KEY=-----BEGIN PRIVATE KEY-----\nzzzzzzzz\n-----END PRIVATE KEY-----\n

The app.js file:

const dotenv = require('dotenv');
dotenv.load();

var admin = require("firebase-admin");
admin.initializeApp({
  credential: admin.credential.cert({
      projectId: process.env.FIREBASE_PROJECT_ID,   // I get no error here
      clientEmail: process.env.FIREBASE_CLIENT_EMAIL,   // I get no error here
      privateKey: process.env.FIREBASE_PRIVATE_KEY   // I get error HERE
  }),
  databaseURL: process.env.FIREBASE_DATABASE_URL
});

How can I fix this issue?

The problem was since I used dotenv variables inside the .env file the FIREBASE_PRIVATE_KEY had escaping characters: \n inside of it.

I had to follow this answer and append .replace(/\\n/g, '\n') to the end of it to parse it:

privateKey: process.env.FIREBASE_PRIVATE_KEY.replace(/\\n/g, '\n')

So now the code looks like:

admin.initializeApp({
  credential: admin.credential.cert({
      projectId: process.env.FIREBASE_PROJECT_ID, // I get no error here
      clientEmail: process.env.FIREBASE_CLIENT_EMAIL, // I get no error here
      privateKey: process.env.FIREBASE_PRIVATE_KEY.replace(/\\n/g, '\n') // NOW THIS WORKS!!!
  }),
  databaseURL: process.env.FIREBASE_DATABASE_URL
});

You must add your key into double qoutes to allow expanded new lines option according with dotenv documentation.

You can check that option at Rules section in dotenv github.

https://github.com/motdotla/dotenv#rules

  FIREBASE_PROJECT_ID=wwwwwwww
  FIREBASE_CLIENT_EMAIL=xxxxxxxx
  FIREBASE_DATABASE_URL=yyyyyyyy
  FIREBASE_PRIVATE_KEY="-----BEGIN PRIVATE KEY-----\nzzzzzzzz\n-----END PRIVATE KEY-----\n"