FISMA

What is it

Fisma is a 422b (br,min) **fi**nite **s**tate _ma_chine that is built on Generators. It features entry/exit actions, events, sending signals to transition to a specific state.

How to use

import { createMachine } from 'fisma';

const m = createMachine([
    'A',
    { type: 'B' },
    {
        type: 'C',
        // Add enter and exit 
        // action as a method
        // or array of actions
        enter() {},
        exit: [() => {}]
    },
    {
        type: 'D',
        on: {
            RESTART: 'A'
        }
    },
    {
        type: 'E',
        on: {
            RESTART: {
                target: 'A',
                actions: [ () => console.log('Running actions') ]
            }
        }
    }
]);

// getters
m.current; // A (The active state)
m.done; // false (is the machine running)

// Use `next` to go to the
// next state in array order
m.next();

m.current; // B

// `.subscribe()` returns a cleanup function
const unsub = m.subscribe((ctx) => console.log(ctx));
m.next(); // { type: 'B' }
m.next(); // { type: 'C' }
unsub();

// Pass a string with the
// name of the desired next state
m.next('A');

m.current; // A

m.next('D');
// Signal to the machine a specific
// state to transition to
m.send('RESTART');

m.current; // A

m.next('E');
m.send('RESTART'); // Running actions

m.destroy(); // kills machine
m.done; // true

Things to be aware of

• There isn't a .start(initialState) method. The initial state is always the first item in the states array.
• While actions are passed a "context" object, currently the context is the active state object and it is not safe to store or alter that information.
• active and done might be confusing, active is for the name of the active state, done is the status of the machine itself. active has been changed to current

To Do

• Give a proper "context" object for actions and listeners
• Accept a more complex "requested state" in the .next() method
• Review method and getter names, e.g. active vs. current, next() vs. somethingElse()
• Should there be an initial getter
• Shave bytes