ESLint error while trying to deploy firebase functions

Easy fix. Inside your package.json change

> "lint": "eslint ."

to

"lint": "eslint",

The only way I can imagine that your project got into this state is if you refused to allow npm to install dependencies at the time of project creation. So when you asks you this:

? Do you want to install dependencies with npm now?

You may have answered 'No'. This would prevent the eslint package from being installed, and you would see that error.

Otherwise, you may have deleted the eslint installed package under node_modules somehow. You can run npm install from the functions folder to recreate everything needed under node_modules.