onion-lasagna-bounded-context

Onion Lasagna Bounded Context

Overview

Create bounded contexts with explicit domain, app, infra, presentation, bootstrap, and public exports.

Always First

Inspect existing bounded contexts, module roots, package exports, and tests before creating files. Match local naming and bootstrap patterns instead of inventing a new convention.

Standard Layout

bounded-contexts/<name>/
|-- domain/
|-- app/
|-- infra/
|-- presentation/
|   |-- bootstrap/
|   |   `-- index.ts
|   `-- http/
`-- index.ts

Bootstrap Pattern

export function bootstrap<Name>() {
  const adapters = createAdapters();
  const useCases = createUseCases(adapters);
  return { adapters, useCases };
}

Public Exports

• Context index.ts exports domain and app contracts.
• Export bootstrap factories when the composition root needs them.
• Do not export concrete infra classes as public API unless an existing package convention requires it.

Guardrails

• Domain exports domain concepts only.
• App exports use cases and ports.
• Infra implements app outbound ports.
• Presentation contains transport handlers and the bootstrap composition root.
• Bootstrap is the only place that constructs concrete dependencies.
• Do not create empty folders that the next task will not use.