Firebase emulator for Cloud Functions not updating the code

Question

I'm deploying the following cloud function using firebase deploy --only functions :

export const testFunction = functions.https.onCall((data, context) => {
  return {"data": "hello"};
});

and when call it from the client app using the code

var testFunction = firebase.functions().httpsCallable("testFunction");
      testFunction().then((result) => {
        // Read result of the Cloud Function.
        this.data = result.data;
});

it works as expected. Now, I want to continue developing the function testing it on the local emulator so, following the documentation, I added this line to the web app code (before the function)

firebase.functions().useEmulator("localhost", 5001); // for local simulator

and I run the local emulator with:

firebase emulators:start --only functions

If I run the client app now, I correctly see the call going through the local emulator instead of the remote cloud function.

Problem: If modify the code the local function doesn't get updated. I need to run firebase deploy again in order to see the change in the response. How can I just deploy locally?

Answer 1

This stackoverflow solves the issue.

Solution in short:

• After every change in your code, run npm run build to recomplie the code.

• To auto-compile for every change in your code. Change "build": "tsc" to "build": "tsc -w" in your package.json file, and run the emulator in an another terminal window.