Service

A service declares a typed dependency. You declare it once, list it in uses, and supply it in wire().

Import

import { integer, service } from '@marcelsud/accord'

Usage

const DepositRules = service('DepositRules', { maximum: integer })

const Account = aggregate(
  'Account',
  { balance: 0 },
  ({ state, emit, rules }) => ({
    deposit(amount: number) {
      if (amount > rules.maximum) return fail(DepositLimit({ maximum: rules.maximum }))
      // ...
    },
  }),
  { uses: { rules: DepositRules } }
)

const bank = wire(Bank, { services: { rules: { maximum: 1_000 } } })

Where uses goes

Definition	Where	Received as
Factory aggregate	4th argument { uses }	factory context, ctx.rules
Command	contract uses	context argument
Policy / projection	contract uses	second handler argument
External / workflow	contract uses	ctx / run.services

Rules

• Service names identify dependencies and must be unique.
• Each alias must refer to the same dependency throughout a model.
• actor, signal, commandId, at, idempotencyKey, services, step, wait, and sleep are reserved aliases.
• A dependency can be a service() or an external() operation.
• Supplied service values are validated against the service schema.
• Commands receive trusted metadata from the runtime. HTTP callers can't supply an actor or dependency bindings.

With Effect

effectify(DepositRules) returns a stable Effect service key:

const RulesLive = Layer.succeed(effectify(DepositRules), { maximum: 1_000 })