Modules, Features and Slices

Module

The module is the top-level namespace and maps to a bounded context. One module per file is the convention but not enforced.

module <Name>

  [<layouts>]
  [<features>]

Layout templates declared at module level are described in Screens.

Features

Features are vertical slice groupings. They nest arbitrarily deep for sub-features.

feature <Name>
  [feature <Name>]*   ← sub-features
  [slice <type> <Name>]+

Slices

The slice is the atomic unit of behavior, aligned with Event Modeling. A slice has a type and a name, and contains the constructs that implement the behavior.

slice <SliceType> <Name>
  <constructs>

Slice types

Type	Description
StateChange	A command → events flow; something that changes the system
StateView	A query + projection + screen; something that reads the system
Automation	A reactor or reducer; something that reacts to events
Translate	A capture; converts external data into events

What goes in a slice

Construct	Typical slice type	Page
event	any	Events
command	StateChange	Commands
constraint	StateChange	Constraints
query	StateView	Queries
projection	StateView	Projections
screen	StateView	Screens
reactor	Automation	Reactors
capture	Translate	Captures

Example

module Invoicing

  feature InvoiceManagement

    slice StateChange RegisterInvoice
      command RegisterInvoice
        ...
      event InvoiceRegistered
        ...

    slice StateView InvoiceList
      query ListInvoices => InvoiceListReadModel[]
      projection InvoiceList => InvoiceListReadModel
        ...
      screen InvoiceList
        ...