What is controller in AngularJS?

A controller is a set of JavaScript functions which is bound to a specified scope, the ng-controllerdirective. Angular will instantiate the new controller object, and injects the new scope as a dependency. It contains business logic for the view and avoids using controller to manipulate the DOM. Controller Rules • We can use controller to set up the initial state of the scope object and add behavior to that object. • We do not use controller to manipulate DOM. It should contain only business logic and can use data binding and directives for the DOM manipulation. • We do not use controllers to format input but can use angular from controls instead of that. • We do not use filter output but can use angular filters instead of that. • We do not use controllers to share code or state across controllers but can use angular services instead of that. • We do not manage the life-cycle of other components. Creating a Controller • Requires ng-controller directive. • Add controller code to a module. • Name your controller based on functionality. • Controllers are named using camel case (i.e. SimpleController). • Setup the initial state of the scope object. ng-Controller directive ng-Controller directive is an associated controller class to the view. How to use ng-Controller 1. 2. 3. 4.