Firebase-firestore.js cannot work on iOS Safari 9

[wira]

• Operating System version: iOS 9.3.5
• Firebase SDK version: 5.0.4
• Firebase Product: app, auth, firestore

[REQUIRED] Describe the problem

Firebase firestore is not working on iOS Safari 9 because of an error in the firebase-firestore.js file. on console: Strict mode does not allow function declarations in a lexically nested statement.

Steps to reproduce: (in iPad)

• Load the script
  `<script src="https://www.gstatic.com/firebasejs/5.0.4/firebase-app.js"></script> <script src="https://www.gstatic.com/firebasejs/5.0.4/firebase-auth.js"></script> <script src="https://www.gstatic.com/firebasejs/5.0.4/firebase-firestore.js"></script>`
• Create firebase object
  firebase.initializeApp(firebaseConfig); const db = firebase.firestore();

[google-oss-bot]

Hey there! I couldn't figure out what this issue is about, so I've labeled it for a human to triage. Hang tight.

[google-oss-bot]

Hmmm this issue does not seem to follow the issue template. Make sure you provide all the required information.

[billyz313]

This is also true in:
safari 5.1 browser on windows 10 using firebase 5.1.0

[Feiyang1]

The issue has been fixed by #1239