Right side of assignment cannot be destructured

[tbence94]

Operating System

iOS 18.5

Environment (if applicable)

Mobile Safari 18.5

Firebase SDK Version

11.9.1

Firebase SDK Product(s)

Auth

Project Tooling

Angular 19.2.14

Detailed Problem Description

I noticed this bug in our sentry.

TypeError: Right side of assignment cannot be destructured
  at <anonymous>(node_modules/@firebase/auth/dist/esm2017/index-8e6e89cb.js:8327:9)
  at o(/chunk-GEF645E4.js:1:1563)
  at zone._inneronInvoke(node_modules/@angular/core/fesm2022/core.mjs:6414:25)
  at {_ZoneImpl#2}.run(node_modules/zone.js/fesm2015/zone.js:111:37)
  at <anonymous>(node_modules/zone.js/fesm2015/zone.js:2430:30)
  at zone._inneronInvokeTask(node_modules/@angular/core/fesm2022/core.mjs:6403:25)
  at {_ZoneImpl#2}.runTask(node_modules/zone.js/fesm2015/zone.js:164:39)
  at drainMicroTaskQueue(node_modules/zone.js/fesm2015/zone.js:567:23)
  at ZoneTask.invokeTask(node_modules/zone.js/fesm2015/zone.js:477:11)
  at invokeTask(node_modules/zone.js/fesm2015/zone.js:1092:12)
  at globalCallback(node_modules/zone.js/fesm2015/zone.js:1122:21)

And the stack trace led me here:

firebase-js-sdk/packages/auth/src/platform_browser/persistence/indexed_db.ts

Line 373 in ab5c2a0

for (const { fbase_key: key, value } of result) {

Maybe the result variable should be type checked more thoroughly.

Steps and code to reproduce issue

I don't know how to reproduce it.

[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.

[hsubox76]

There's probably not a lot we can do without a reproduction. There's enough info to see that there's some kind of IndexedDB problem and you mentioned the browser is mobile Safari, which is known to have some quirks when it comes to IndexedDB. Unfortunately those quirks are not documented so it's hard to guess what's going wrong without being able to reproduce and dig into it locally.

Do you at least have a sample of code showing how you use auth in your app, or if it's too many places, a list of what methods from auth you use? (onAuthStateChanged, signInWithEmailAndPassword, etc.)?

[hijamoya]

I have the same issue for iOS 18.5:

TypeError Right side of assignment cannot be destructured 
    dist/browser/zh-Hant/node_modules/@firebase/auth/dist/esm2017/index-8e6e89cb.js:8327:8 
    dist/browser/zh-Hant/node_modules/@angular/core/fesm2022/core.mjs:6414:31 onInvoke
    dist/browser/zh-Hant/node_modules/zone.js/fesm2015/zone.js:111:49 run
    dist/browser/zh-Hant/node_modules/zone.js/fesm2015/zone.js:2538:43 
    dist/browser/zh-Hant/node_modules/@angular/core/fesm2022/core.mjs:6403:35 onInvokeTask
    dist/browser/zh-Hant/node_modules/zone.js/fesm2015/zone.js:159:57 runTask
    dist/browser/zh-Hant/node_modules/zone.js/fesm2015/zone.js:581:42 X
    dist/browser/zh-Hant/node_modules/zone.js/fesm2015/zone.js:487:40 invokeTask
    dist/browser/zh-Hant/node_modules/zone.js/fesm2015/zone.js:1138:24 S
    dist/browser/zh-Hant/node_modules/zone.js/fesm2015/zone.js:1169:39 Z

We’re using the following Firebase Auth methods:

import {
  getAuth,
  signInWithCustomToken,
  UserCredential,
  signOut,
} from 'firebase/auth';

This issue doesn’t consistently occur on a specific page or method call. It appears to be related to the internal state management of the Firebase Auth instance. It can happen anywhere.

•	Firebase version: 11.9.1
•	Framework: Angular 19.2.14
•	Platform: iOS 18.5 Safari

Any insights or workarounds would be appreciated.

Thanks!

[hsubox76]

Looks like result is an array of DBObject retrieved from IndexedDB. There's a check that the result array isn't empty, but not a check that the the elements in the array are legit DBObjects. I guess first I'd really like to understand what kind of unusual element IndexedDB considers worthwhile to return, that isn't undefined but also isn't destructurable, so that we know what to check for and how to handle it. We can just return an empty array but if there's any actual data in there that we could have used, this will lead to persistence just not working in the cases where this used to throw an error, which I don't think is ideal. If the return value really is nonsense (null or some error object) then we should go ahead and do that, though.

Is anyone experiencing this able to log the value of result[0] when it happens? Actually all the elements in result - it might not necessarily be erroring on the first element.