First log it to the JS console (only once, no duplicates) then show it on the screen with the error dialog. Every (uncaught) client side exception must do that, so no exceptions gets swept under the rug.

See this screenshot:

Notice that it hasn't show up in the JS console. One reason the JS console is important is to clearly see the order of things when the error is for example mixed with debug messages. Also, if for some reason the error dialog fails itself (which should never happen of course), then at least it's in the log.

to reproduce: open the new roster screen in the branch and select the second to last tenant. Or just temp throw an exception in the client side code that runs when you click the solve button