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I love this, is there any conversation or references anywhere about where it came from?

I love this, is there any conversation or references anywhere about where it came from?

Some conversation here: https://discord.com/channels/795785288994652170/1169717611416789083

It builds up from previous discussions about a capture() API, but most recently, just the frustration in typing choose() and pure() 😅

How will it behave with async logic?

I imagine new users will attempt something like this:

actions: createAction(async ({ context, event, exec }) => {
  exec.assign({ isFetching: true });
  
  const res = await fetchTodos(1000);
  
  exec.assign({ todos: res.data, isFetching: false });  
})

Async logic would not be permitted here

Async logic would not be permitted here

Sounds perfect to me 👌

Also, I'm curious, what is the reason behind using exec.assign / exec.action / etc..
over just exec(assign({}))?

Are they just shortcuts for better DX?

While I do like it, I wonder about the case of using a custom assign, like @xstate/immer.
If the rest of the machine is using @xstate/immer's assign, it may be confusing to have access to the default assign on exec.assign.

Without the shortcuts, it's one less thing to think about.

import { assign } from '@xstate/immer';

//...

actions: [
  // a custom assign imported from "@xstate/immer"
  assign(({ context }) => {
    context.value = 'foo';
  }),
  createAction(({ context, event, exec }) => {
    // The assign we're using for the rest of the machine
    exec(assign({
      count: context.count + 1
    }));
  })
]

What do you think?

Also, I'm curious, what is the reason behind using exec.assign / exec.action / etc..
over just exec(assign({}))?

Makes typing stronger; no need to infer types, which isn't perfect. We can strongly type exec.assign etc. upfront.

Without the shortcuts, it's one less thing to think about.

Note that this should still "just work" - so you can very much do this.