action

action

action takes a function that will be run during a transition. The primary purpose of using action is to perform side-effects.

This example triggers an event on an element when transitioning to the next state.

import { createMachine, action, state, transition } from 'robot3';

function dispatchOn(ctx) {
  const { element } = ctx;
  element.dispatchEvent(new CustomEvent('toggled'));
}

const machine = createMachine({
  on: state(
    transition('toggle', 'off')
  ),
  off: state(
    transition('toggle', 'on',
      action(dispatchOn)
    )
  )
}, () => ({
  element: document.querySelector('#toggler')
}));