httpsCallable throws `invalid-argument` error when the response status is not 200

[NayamAmarshe]

Operating System

macOS

Environment (if applicable)

Node.js 22, Firebase Functions 2, Next.js 14

Firebase SDK Version

11.4.0

Firebase SDK Product(s)

Functions

Project Tooling

I'm using Next.js 14 along with Firebase Functions emulator.

Detailed Problem Description

• When calling an onRequest function from the client using httpsCallable, it should return the correct response back.
• From the functions side, if we return a response message, it should be parsable by the client.
• However, when the status code is anything other than 200, the httpsCallable directly throws an invalid-argument error.

Unhandled Runtime Error
FirebaseError: invalid-argument

Steps and code to reproduce issue

function:

import { onRequest } from "firebase-functions/https";
import { logger } from "../lib/logger";

export type TestRequest = {
  status: string;
  message: string;
};

export const test = onRequest(
  {
    cors: true,
    timeoutSeconds: 60,
    region: ["us-central1"],
  },
  async (req, res) => {
    logger.info("createLink called!", { structuredData: true });
    console.log("🚀 => req.body:", req.body);
    res.status(400).send({
      status: "error",
      message: "Missing required fields",
    });
  },
);

client:

import { functions } from "@/lib/firebase/firebase";
import { httpsCallable } from "firebase/functions";
import React from "react";

const TestPage = () => {
  const test = async () => {
    const createLink = httpsCallable(functions, "test");
    const response = await createLink();
    console.log(response);
  };
  return <button onClick={() => test()}>Test</button>;
};

export default TestPage;

[google-oss-bot]

I couldn't figure out how to label this issue, so I've labeled it for a human to triage. Hang tight.

[DellaBitta]

Hi @NayamAmarshe,

I think the issue might be in format of the error response. The object should include an error field:

response.status(400).send({
  error: {
    status: 'THIS_IS_NOT_VALID',
    message: 'this should be ignored'
  }
});

I just tested this format on one of our test functions and it worked as intended. I hope this helps!