States - Beautiful Finite State Machine (FMS) for Dart #

API: #

abstract class IStates {
  String get current;
  bool get locked;
  List<StatesTransition> get all;
  
  List<StatesTransition> actions({String from});
  List<StatesMeta> metas({String from});
  
  StatesMeta add( String state );
  StatesTransition when({
    String at,
    String to,
    String on,
    StatesTransitionFunction handler
  });
  
  String subscribe(StatesTransitionFunction listener);
  bool unsubscribe(String subscriptionKey);
  
  bool change({ String to, bool run = true });
  bool has({
    String action,
    String state,
    bool conform = true
  });
  StatesTransition get( String action );
  bool execute( String action );
  bool on(String action, StatesTransitionHandler listener);
  
  void reset();
  void dispose();
  
  void lock({@required String key});
  void unlock({@required String key});
}

Usage #

A simple usage example: #

 States states = new States();

 states.add( STATE_INITIAL );

 states.add( STATE_LOADING );
 states.add( STATE_LOADING_COMPLETE );
 states.add( STATE_LOADING_FAILED );

 states.when(
   at: STATE_INITIAL,
   to: STATE_LOADING,
   on: ACTION_LOADING_START,
   execute: (StatesTransition action) {
     print("> CURRENT on ACTION_LOADING_START state: " + states.current);
     scheduleMicrotask(() {
       print("> \t END OF microtask queue -> state: " + states.current);
       var nextBool = Random.secure().nextBool();
       print("> \t\t next bool: " + nextBool.toString());
       states.run( nextBool ? ACTION_LOADING_COMPLETE : ACTION_LOADING_FAILED );
       });
     });
 
 states.when(
   at: STATE_LOADING,
   to: STATE_LOADING_COMPLETE,
   on: ACTION_LOADING_COMPLETE,
   execute: (StatesTransition action) {
     print("> CURRENT on ACTION_LOADING_COMPLETE - state: " + states.current);
     scheduleMicrotask(() => print("> \t END OF microtask queue -> state: " + states.current));
   }
 );
 
 states.when(
   at: STATE_LOADING,
   to: STATE_LOADING_FAILED,
   on: ACTION_LOADING_FAILED,
   execute: (StatesTransition action) {
     print("> CURRENT on ACTION_LOADING_FAILED state: " + states.current);
     scheduleMicrotask(() => print("> \t END OF microtask queue -> state: " + states.current));
   }
 );
 
 states.run( ACTION_LOADING_START );

SPA with States #

Please take a look how this library can help to create SPA with simple dart:html See folder example/spa_with_states