There is a javascript error and the alert is not loaded

Is this still an issue with the 2.1.1 release? That release removed a JavaScript dependency that may have been causing the problem.

I checked after updating to version 2.1.1, and still the same issue when:
AdvAgg Minify CSS
AdvAgg Minify JavaScript
are enabled.

not related to AdvAgg as not installed and still getting JS error mentioned above. This was first attempt at 2.x branch so can't say if this just broke.

tried 2.0.2 and still errors. I see backticks in the js code as opposed to single quotes. Didn't think that was valid but i guess for ES6; although this isnt ES6.

Mystery solved (for me anyway).. i was overriding the class public function activeVisibleSitewideAlerts() but this changed between 1.6 and 2.x to declare as an array:

public function activeVisibleSitewideAlerts(): array {}

i could see this when i went to the controller path http://local/sitewide_alerts/load.

I am not able to reproduce this. Reopen or create a new issue if this is still an issue with the latest version of this module.