What causes typescript compile error when deploying

I roughly following this tutorial to make a cloud function with typescript. It works fine in development, but when I try to deploy it (firebase deploy --only functions), I get A LOT of typescript errors. I have no idea why. It works in dev, why can't I push the same set up to Firebase?

Follow the below steps for a successful cloud functions deployment:

• After you have created a Firebase project using this step, install the Firebase CLI using : npm install -g firebase-tools.
• Run firebase login to log in via the browser and authenticate the firebase tool.
• Run firebase init firestore
• Run firebase init functions
• When you run firebase init functions, there will be prompts, 1st prompt : “What language would you like to use to write Cloud Functions?” -> Choose Typescript. 2nd prompt : Do you want to use ESlint to catch probable bugs and enforce style (y/n)? -> Choose n. By selecting no you will be saving yourself from the typescript compile errors.
• Once initialization is complete, uncomment the sample in index.ts and run npm run serve to see a "Hello World" function in action. Once you can see the output in Firebase emulator, you will know the functions executed properly.
• Now, before you deploy the functions, assign the Cloud Functions Invoker, Cloud Functions Admin and Cloud Functions Developer role to project-id@appspot.gserviceaccount.com
• Now run firebase deploy –-only functions. The deployment will be successful but the browser might show 403 errors ( Client does not have permission..) For that, select your cloud function (check box) click "Add members" under the Permissions tab in the right side, enter "allUsers" under "New members", select Role as Cloud Functions -> Cloud Functions Invoker and then save the configuration.
• If you do not want to give public access to your cloud functions, you can set up authentication, by skipping the previous step. In Cloud Shell, run gcloud auth print-identity-token. This outputs a token which you will be authenticating your cloud function with. Now provide authentication credentials in your request as a Google-generated ID token stored in an Authorization header with this command :

curl https://REGION-PROJECT_ID.cloudfunctions.net/FUNCTION_NAME \ -H "Authorization: bearer $(gcloud auth print-identity-token)"