AngularJS

AngularJS is a structural framework for dynamic web apps. It lets you use HTML as your template language and lets you extend HTML’s syntax to express your application’s components clearly and succinctly. Angular’s data binding and dependency injection eliminate much of the code you would otherwise have to write.

Angular 2 represents a massive change to the framework. Everyone spent so much time learning the odd language of v1 (directive, anyone?), understanding how scopes work, spending time debugging ngModel issues, and trying to figure out the perfect folder structure, and now almost all of that is changing.