How to return list of transitions and states that are allowed from the current state

[peng-huang-ch]

const timeOfDayMachine = Machine({
  id: 'timeOfDay',
  initial: 'unknown',
  context: {
    time: undefined
  },
  states: {
    // Transient state
    unknown: {
      on: {
        'ACTION': [
          { target: 'morning', cond: 'isBeforeNoon' },
          { target: 'afternoon', cond: 'isBeforeSix' },
          { target: 'evening' }
        ], 
        'ACTION2': "morning"
      }
    },
    morning: {},
    afternoon: {},
    evening: {}
  }
}, {
  guards: {
    isBeforeNoon: ()=> {},
    isBeforeSix: () => {}
  }
});
// currentState is unknown
// return list of transitions that are allowed from the current state 
// => ["ACTION", "ACTION2"]

// return list of states that are allowed from the current state 
// => 'isBeforeNoon'  -> ["morning"]
// => 'isBeforeSix'  ->  ["afternoon", "morning"]
// =>  ->  ["evening", "morning"]

[MrNovado]

@penghap
As far as I know, xstate model (Schema | Context | Event) does not allow you to describe those restrictions currently. Also, no idea whether or not those are planed, but it would be neat to be able to do that out of the box.

I made a proposal some time ago about related topic:
#1056

And a proof of concept tool to generate those state2EventMap models:
#1056 (comment)
https://github.com/MrNovado/xstate-gentype-proof/blob/v1.0.0-simple/src/simple.machine.gen.ts#L160

And you can make those maps yourself, but then again they won't be coupled with your xstate-Schema and their maintenance will be entirely on you.

[mattpocock]

@MrNovado @penghap This falls under the remit of what xstate-codegen is trying to accomplish. If you're interested, the beta is available on npm under the 'next' flag.