Angular.js was developed by Google and was released in 2010. As of now it is maintained by community and Google itself. According to Libscore, Angular is used on more than 12 thousand sites, with top rated three reading:
○ Diply.com #59
○ Weather.com #174
○ Gfycat.com #177

Similarly to ReactJS, Angular principles suppose that components connections and user interfaces are better done with declarative programming technique. Angular JS separates DOM manipulation from application logic, and separates the client and server sides of an application. Two-way data binding, the behavior of the framework implying that any alterations to the view are reflected in the model, whilst changes in the model, detected by $scope, alter HTML expressions in the view via a controller, eases the templating work for the server back-end.
"Angular.js allows to write a clean and error-tolerant code of a web application. This framework is extremely useful for creating a Single Page Application in a very transparent and sustainable way."
The AngularJS framework reads an HTML page with custom tag attributes embedded, interprets those attributes and binds i/o parts to a model. The values of JavaScript variables representing that model can be both set manually within the code, or retrieved from JSON resources. AngularJS checks for changes to all the variables watched by all the $scopes in a cycle, called digest cycle. Big numbers of watched variables can seriously hinder the work, so Miško Hevery, the original developer of Angular JS, suggests not to exceed 2000 watchers on a single page.