Xstate: Be able to call assign actions with ActionObject notation

[carloslfu]

Bug or feature request?

Feature request

Description:

Be able to call assign actions using the ActionObject notation, it's also needed to implement <param> and <content> which would be placed into the event (per the SCXML spec).

Example:

onEntry: { type: 'myAction', foo: 'bar' }

// ...

actions: {
  myAction: (ctx, e) => {
    e.foo === 'bar'; // true
  }
}

Anything passed into the action object will be merged with the event object.

[davidkpiano]

Clarification with this after reading the spec: the extra fields passed into the action object will be merged with the resolved action object, not with the event:

onEntry: { type: 'myAction', foo: 'bar' }

// ...
actions: {
  myAction: (ctx, e) => {
    e.foo === undefined;
  }
}

But when that action is returned as part of the State, it is returned as:

{
  type: 'myAction',
  foo: 'bar',
  exec: (ctx, e) => { e.foo === undefined; }
}

Which makes me think that we should pass the action as a 3rd argument to the action?

[carloslfu]

Which makes me think that we should pass the action as a 3rd argument to the action?

Yes, I think it is a good solution.

[davidkpiano]

Added in the 3rd argument in the actionMeta property as of version 4.4. Docs: https://xstate.js.org/docs/guides/actions.html#declarative-actions