SyntaxError: Unexpected private name #o. Cannot parse class method with private name.

[jozefizso]

NewRelic browser monitoring agent fails in web view on macOS.

Description

Our website is using the NewRelic monitoring agent.

Steps to Reproduce

1. Create macOS app with a web view.
2. Run the app on macOS 11 or macOS 12
3. Load website with NewRelic monitoring agent
4. Page fails to load and a fatal SyntaxError prevents any other JS code to execute.

Expected Behavior

NewRelic will monitor correctly the website in any browser the customer is using.

The SyntaxError is so fatal we cannot even run the error handler code to display an error message, or log it to the server.

The NewRelic monitoring agent does not capture the error caused by the @newrelic/browser-agent library.

Relevant Logs / Console output

SyntaxError: Unexpected private name #o. Cannot parse class method with private name.

Your Environment

• Safari 14, 15, 16
• macOS 11
• Browser agent version: 1.246.0

[workato-integration]

https://new-relic.atlassian.net/browse/NR-358840

[cwli24]

Note that per https://docs.newrelic.com/docs/browser/new-relic-browser/getting-started/compatibility-requirements-browser-monitoring/#browser-types , webviews and particularly macOS are not officially supported by the agent. The support statement relates to native browsers on PCs (and Android+iOS devices).

It sounds like the agent code syntax is incompatible (or possibly being mutated) with the macOS 11 and 12 environments. In this case, you'll have to fork and self-maintain a custom build of the agent with corrected browser targets in the babel config.