> but your progressively-enhanced client-side logic (i.e. JS) still wasn't necessarily easy to debug, let alone being able to write unit tests for them
True, don't remember doing much unit testing of JavaScript at that point. Even with BackboneJS and RequireJS, manual testing was pretty much the approach, trying to make it easy to repeat things with temporary dev UIs and such, that were commented out before deploying (FTPing). Probably not until AngularJS v1 came around, with Miško spreading the gospel of testing for frontend applications, together with Karma and PhantomJS, did it feel like the ecosystem started to pick up on testing.
True, don't remember doing much unit testing of JavaScript at that point. Even with BackboneJS and RequireJS, manual testing was pretty much the approach, trying to make it easy to repeat things with temporary dev UIs and such, that were commented out before deploying (FTPing). Probably not until AngularJS v1 came around, with Miško spreading the gospel of testing for frontend applications, together with Karma and PhantomJS, did it feel like the ecosystem started to pick up on testing.