crates.io fails to load on Edge for Android

[Turbo87]

Describe the bug

see https://twitter.com/zkat__/status/1425654525730373637

To Reproduce
Steps to reproduce the behavior:

1. Install "Edge" on an Android device
2. Visit crates.io

Expected behavior

It should show the regular content

Smartphone

• Device: OnePlus 8
• OS: Android 11
• Browser: Edge 46.06.4.5161

[Turbo87]

I've debugged this using the instructions at https://docs.microsoft.com/en/microsoft-edge/devtools-guide-chromium/remote-debugging/ resulting in a console error:

Uncaught SyntaxError: Unexpected token '?'

with the stacktrace leading to:

It looks like Edge for Android is currently using an old JS engine, which does not support the (Nullish Coalescing Operator)[https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Nullish_coalescing_operator] yet, and our targets.js file allows the operator to pass through without transpilation.

[Turbo87]

somewhat related and making the fix for this unnecessarily complicated:

• How do you count Microsoft Edge browsers for iOS and Android Fyrd/caniuse#5473
• Add Edge Mobile to the browsers list Fyrd/caniuse#5492
• Microsoft Edge latest version in Android browserslist/browserslist#493

[Turbo87]

I can also confirm what is stated in Fyrd/caniuse#5473 (comment). With "Edge Beta for Android" the app loads fine.