sicoris-statemachine-js

Simplified state machine library for JS, following most of the principles of https://bitbucket.org/xferro/sicoris-statemachine but with just non-reentrant strategy.

It is a very lightweight but powerful library. A State Machine consists of the following:

* A set of states. One and only one is the start state. We can have multiple final states
* A set of events that can be processed by the state machine
* A set of transition. A transition is a tuple of: source state, event and target state.
* Each transition has three phases
Exit or leave phase: when the transition starts, it's the only phase where we can cancel the transition
Transition phase: where we do all the work
Enter phase: sometimes, we want to force the transition to move to another state. Useful for condition states
* If we try to process an event, and the transition has not been defined, it will throw an exception.


Installation

This module is installed via npm:

`` bash
$ npm install sicoris-statemachine-js
`

Example Usage with some conditions

` js
var stateMachine = require('sicoris-statemachine-js');
git
var cfg = { // State machine with 2 states: STATE_A and STATE_B
STATE_A : {
startState: true, // When the SM is created, it will be initialized to STATE_A
transitions: {
EVENT_AB : "STATE_B" // When in STATE_A, we can trigger a transition by processing EVENT_AB
}
},
STATE_B : {
endState: true // STATE_B is a final state
}
};

var def = stateMachine(cfg);
var processor = def.processorBuilder()
// We can register a listener when exiting a state
.onExit("STATE_A", function(transition) {
console.log("leaving state " + transition.source
+ " to state " + transition.target
+ " because of event " + transition.event);
return true; // Returning true allows the transition to continue
})
.onEnter("STATE_B", function(transition) {
console.log("entering " + transition.target
+ " from state " + transition.source
+ " because of event " + transition.event);
})
.onTransition("STATE_A", "EVENT_AB", function(transition) {
console.log("transitioning from state " + transition.source
+ " to state " + transition.target
+ " because of event " + transition.event);
})
.build();

console.log(processor.getCurrentState());
processor.process(EVENT_AB);
console.log(processor.getCurrentState());
``