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ddd-ts-kit

ddd-ts-kit/ports-no-token-constant

Architecture id: ports/no-token-constant. Default severity: error in recommended, error in strict.

Applies to: every linted file.

Why

Section titled “Why”

A port class is its own injection token. A constant next to it, a token(..) helper, a symbol or a string is a second name for the same thing: it has to be kept in step by hand, it loses the type, and it hides the dependency list from the compiler.

Reported

Section titled “Reported”
  • a call of token, imported from a package of the kit (@ddd-ts-kit/*), by name, by alias or through a namespace
  • Symbol(..), Symbol.for(..) or a string literal given as first argument of a binding call, and a variable declared as such a symbol given to one
  • an identifier in upper snake case (two characters at least) in a dependency list
  • a file named *.ports.ts or tokens.ts under the source root, reported on its first line

Incorrect:

// a constant that stands for the port, in a file that collects them
export const invoiceRepositoryToken = Symbol('billing.InvoiceRepository');


builder.bind(invoiceRepositoryToken).toClass(KnexInvoiceRepository, [Database]);
builder.bind('clock').toValue(clock);

Correct:

domain/repositories/invoice.repository.ts
export abstract class InvoiceRepository extends Repository<Invoice> {}


builder.bind(InvoiceRepository).toClass(KnexInvoiceRepository, [Database]);
builder.bind(Clock).toValue(clock);

Details

Section titled “Details”

A dependency list is the array that names what a constructor receives: the last argument of a declaration decorator of @ddd-ts-kit/kernel/declarations (@CommandHandler(M, [..]), @QueryHandler, @IntegrationEventHandler, @DomainEventHandler, @Scheduled, @Repository, @Gateway, @Adapter, @Policy) and the second argument of .toClass(C, [..]) and .handledBy(H, [..]) of @ddd-ts-kit/di.

A binding call is bind, rebind, resolve, fake or override, plain or as a member (builder.bind(X), app.resolve(X)), and is read only in a file that imports something from @ddd-ts-kit/di; Promise.resolve, path.resolve, require.resolve and import.meta.resolve are never binding calls.

Options

Section titled “Options”

None.

rules."ports/no-token-constant" in ddd-ts-kit.config.json set to off silences the rule, and // ddd-ts-kit-disable-next-line ports/no-token-constant -- <reason> silences one line, exactly as for ddd-ts-kit check.

Limits

Section titled “Limits”
  • A token made by a home-made helper, or a symbol declared in another file, is not followed.
  • An upper snake case name is reported in a dependency list only: a constant of the domain anywhere else is not a token.

With the CLI checker

Section titled “With the CLI checker”

ddd-ts-kit check reports the same id from the text of the files. This rule is the authority for the code.