Why do you even need dependency injection and singleton services and factories in a dynamic language with closures and first-class functions? You don't. Client-side testing works fine without DI. Angular is just a way to do Java in JavaScript. It's a pile of unnecessary complexity designed to sell to enterprises that love over-designed Java projects and want to make client-side development feel more similar to what they know. In that regard I suppose Angular is a little better than Google Web Toolkit, but that isn't saying much.