Keystone: [RFC] A StateMachine type

[jesstelford]

Request For Comments on a new field type StateMachine:

---

StateMachine Field Type

The StateMachine field type allows you specify a Finite State Machine to control the possible states and transitions between those states in a declarative syntax, ideal for setting up publishing workflows or user onboarding walkthroughs.

The StateMachine field type is powered by the xstate.js state chart library.

Example

keystone.createList('Post', {
  fields: {
    name: { type: Text },
    status: {
      type: StateMachine,
      defaultValue: 'draft',
      states: {
        draft: {
          on: {
            ready: [
              { target: 'ready', cond: 'isAdmin' },
              { target: 'ready', cond: 'isAuthor' },
            ],
          },
        },
        ready: {
          on: {
            published: [{ target: 'published', cond: 'isAdmin' }],
            rejected: [{ target: 'rejected', cond: 'isAdmin' }],
          },
        },
        rejected: {
          on: {
            draft: [
              { target: 'draft', cond: 'isAdmin' },
              { target: 'draft', cond: 'isAuthor' },
            ],
          },
        },
        published: {
          on: {
            draft: [{ target: 'draft', cond: 'isAdmin' }],
          },
        },
      },
      guards: {
        isAdmin: ({ context }) => context.authedItem && context.authedItem.isAdmin,
        isAuthor: ({ context, existingItem }) => context.authedItem && context.authedItem.id === existingItem.author,
      },
    },
  },
});

The states and guards are passed straight to xstate.

See the equivalent xstate state machine here (try changing the values returned from isAdmin/isAuthor to see the different transitions which are enabled/disabled):

The AdminUI Field would display as a drop-down of the current state and any possible states which can be reached from there. Something like:

---

Whatchya think?

[VinayaSathyanarayana]

This will be really useful

[stale[bot]]

It looks like there hasn't been any activity here in over 6 months. Sorry about that! We've flagged this issue for special attention. It wil be manually reviewed by maintainers, not automatically closed. If you have any additional information please leave us a comment. It really helps! Thank you for you contribution. :)

[vmdao]

Like it :)

[mahcr]

Is there any update?

[wcalebgray]

Hey all, any updates on this? I think it sounds awesome and my project could really use this functionality as a replacement for the dependsOn feature that was in previous versions of Keystone.

[joseDaKing]

Hi, everbody there is state machine library in javascript called xstate it might can be used for this use case