Generated by XState Viz: https://xstate.js.org/viz

machine.js

  // Available variables:
  // - Machine
  // - interpret
  // - assign
  // - send
  // - sendParent
  // - spawn
  // - raise
  // - actions
  // - XState (all XState exports)
  
const increment = context => context.count + 1;
const decrement = context => context.count - 1;

const counterMachine = Machine({
  initial: 'active',
  context: {
    count: 0
  },
  states: {
    active: {
      on: {
        INC: { actions: assign({ count: increment }) },
        DEC: { actions: assign({ count: decrement }) }
      }
    }
  }
});

const counterService = interpret(counterMachine)
  .onTransition(state => console.log(state.context.count))
  .start();
// => 0

counterService.send('INC');
// => 1

counterService.send('INC');
// => 2

counterService.send('DEC');
// => 1