TypeError: setUserProperty is not a function on Kotlin/JS target Description

[bpappin]

Description

When running firebase-analytics on the Kotlin/JS target, calling the common API function FirebaseAnalytics.setUserProperty(name, value) throws a runtime TypeError: setUserProperty is not a function.

Underlying Cause

In the jsMain actual wrapper for FirebaseAnalytics, the library defines an external binding mapping directly to an export named setUserProperty in the "firebase/analytics" NPM module:

// dev.gitlive.firebase.analytics.externals.analytics.kt
@file:JsModule("firebase/analytics")
@file:JsNonModule
package dev.gitlive.firebase.analytics.externals

public external fun setUserProperty(app: FirebaseAnalytics, name: String, value: String)

However, the official Firebase JS SDK (v9/v10 modular API) does not export a function named setUserProperty (singular) under "firebase/analytics". Instead, the official JS SDK only exports setUserProperties (plural) which takes an analytics instance and a properties object:

import { setUserProperties } from "firebase/analytics";
setUserProperties(analytics, { favorite_food: "apples" });

Because of this, the imported JS function resolves to undefined at runtime, causing any invocation of setUserProperty(...) in Kotlin/JS common code to crash.

Environment Details

• Library Group/Artifact: dev.gitlive:firebase-analytics / dev.gitlive:firebase-analytics-js
• Library Version: 2.4.0
• Kotlin Compiler Version: 2.3.21 (Kotlin/JS)
• Firebase JS SDK NPM version: 10.13.2
• Platform Target: Kotlin/JS (Browser Webpack / Web target)

Steps to Reproduce

1. In commonMain code, instantiate and call Firebase Analytics:

   val analytics = Firebase.analytics
   analytics.setUserProperty("app_os_family", "Web")

2. Build and launch the Kotlin/JS target in a browser environment.
3. The application crashes immediately during initialization with the following stack trace:

   TypeError: setUserProperty is not a function
       at protoOf.setUserProperty_rx7df6_k$ (webpack-internal:///./kotlin/firebase-kotlin-sdk-firebase-analytics.js:225:5)
       at firebaseModule$lambda$lambda (webpack-internal:///./kotlin/EvolynClient-data.js:28802:12)
   

Expected Behavior

The library's setUserProperty(name, value) implementation should map to the official JS SDK's setUserProperties method under the hood:

// Expected jsMain delegation mapping
public actual fun setUserProperty(name: String, value: String) {
    setUserProperties(this.js, json(name to value)) 
}

Workaround / Mitigation

We mitigated this locally in our codebase by declaring the correct external JS binding and using an expect/actual extension to bypass the broken wrapper function on the JS target:

// webMain actual mapping
@file:JsModule("firebase/analytics")
@file:JsNonModule
package app.evolyn.data.firebase

import dev.gitlive.firebase.analytics.externals.FirebaseAnalytics

@JsName("setUserProperties")
public external fun setUserProperties(app: FirebaseAnalytics, properties: dynamic)