getting-started.md

Getting started

A simple state machine can be initiated using the cogwheel function from the package. It allows you to view the current state (machine.current), or invoke a transition via the .send(event: Event, delay?: number) function.

import { machine } from 'cogwheel';

const config = {
  init: 'green',
  states: {
    green: { CHANGE: 'yellow' },
    yellow: { CHANGE: 'red' },
    red: { CHANGE: 'green' },
  },
};

const machine = machine(config);
// machine.current = 'green'
machine.send({ type: 'CHANGE', key: 'value' }, 3000);
// machine.current = 'yellow'

The machine.send function returns a boolean showing if the transition was successful or not. NOTE: this does not work with delayed transitions.

Context

The library also allows for 'extended finite state machine', or in other words: context aware state machines. You can define an intial 'context' as a third parameter in the cogwheel function. You can access the values via the .context attribute of the resulting machine. The context is very useful when using guards or actions.

import { machine } from 'cogwheel';
const machine = machine({ init: 'green', states, context: { count: 0 } });
// machine.context.count === 0

Next: guards