Rules

alveolus arch check applies nine rules. Each one guards against a way a project drifts over time: a shortcut between bounded contexts, a framework leaking into the domain, a helper that lands nowhere in particular. It does not check everything, only what keeps the architecture standing.

Rule	Guards against
bc-isolation	Bounded contexts reaching into each other.
domain-purity	The domain depending on frameworks, databases or other layers.
layer-direction	Dependencies pointing outwards, and files outside the layers.
driven-adapters-extend-port	Adapters that implement no port, ports declared outside the domain.
building-blocks-only	Plain classes, free functions and enums in the domain and the application.
placement	Classes in the wrong folder or file.
reference-by-identity	An aggregate holding another aggregate.
command-query-separation	Commands that read views, queries that write.
errors-as-values	Business failures thrown instead of returned.

Read a violation

Each violation gives the file and the line, the rule, what is wrong and what is allowed instead:

src/ordering/application/commands/place-order.command.ts:4
  layer-direction: The application layer imports src/ordering/driven/pg/adapters/mailer.adapter.ts (ordering driven): it may only import domain, application, published-language.

--format json gives the same information as JSON, with the symbol involved, for tools and agents.

Building blocks are recognised by inheritance

The rules know what a class is from what it extends: class Order extends AggregateRoot is an aggregate, wherever it is and whatever its name. A class that extends one of your own base classes counts too, as long as that base class extends a building block of @alveolus/core. That is why there are no decorators or naming conventions to learn: the class says what it is.

Turn a rule off

Every rule is on by default. Turn one off in alveolus.config.ts:

alveolus.config.ts

export default defineConfig({
	boundedContexts: { ordering: "ordering" },
	root: "src",
	rules: { placement: "off" },
});

To adopt the rules on an existing project without turning them off, record the current violations in a baseline: see Getting started.

Test files (*.spec.ts, *.test.ts, __tests__/) are never checked.