state-machine

class Document < ApplicationRecord
  belongs_to :account

  enum status: { pending: 0, processing: 1, ready: 2, failed: 3 }

  after_create_commit :broadcast_badge

export type CircuitState = "closed" | "open" | "half-open";

export interface CircuitBreakerOptions {
  failureThreshold: number;
  resetTimeout: number; // ms to wait in "open" before probing
  onStateChange?: (from: CircuitState, to: CircuitState) => void;

export const initialState = (steps, initialData = {}) => ({
  steps,
  stepIndex: 0,
  data: initialData,
  errors: {},
});

use std::fmt;

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum OrderState {
    Pending,
    Paid,

export type FetchState<T> =
  | { status: 'idle' }
  | { status: 'loading' }
  | { status: 'success'; data: T }
  | { status: 'error'; error: Error };

class Order < ApplicationRecord
  class InvalidTransition < StandardError; end

  enum status: { pending: 0, paid: 1, shipped: 2, cancelled: 3 }

  has_many :order_transitions, -> { order(:created_at) }, dependent: :destroy