This subsystem implements the ui-router state tree

• The StateService has state-related service methods such as:
  • StateService.get: Get a registered StateDeclaration object
  • StateService.go: Transition from the current state to a new state
  • StateService.reload: Reload the current state
  • StateService.target: Get a TargetState (useful when redirecting from a Transition Hook)
  • StateService.onInvalid: Register a callback for when a transition to an invalid state is started
  • StateService.defaultErrorHandler: Register a global callback for when a transition errors
• The StateDeclaration interface defines the shape of a state declaration
• The StateRegistry contains all the registered states
  • States can be added/removed using the StateRegistry.register and StateRegistry.deregister
    • Note: Bootstrap state registration differs by front-end framework.
  • Get notified of state registration/deregistration using StateRegistry.onStatesChanged.