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ddd-ts-kit

ddd-ts-kit/errors-through-factory

Architecture id: errors/through-factory. Default severity: error in recommended, error in strict.

Applies to: every file of a context, tests included, in a project whose config says "stack.refusals": "factories". A config without the key was written when an error was a class built with new: nothing is reported there.

Why

Section titled “Why”

The code that refuses reads as a sentence, and the refusals of one concept live in one class: throw AppointmentError.slotTaken(calendar.id, slot.startsAt). The factory writes the code, the message and the facts once. A new outside the class is a refusal whose code and message are whatever the caller wrote.

Reported

Section titled “Reported”
  • new X(...) where X is imported from a file of domain/errors/

Incorrect:

import { SlotTakenError } from '@/contexts/scheduling/domain/errors/slot-taken.error';


throw new SlotTakenError(calendar.id, slot.startsAt);

Correct:

import { AppointmentError } from '@/contexts/scheduling/domain/errors/appointment.error';


throw AppointmentError.slotTaken(calendar.id, slot.startsAt);

Options

Section titled “Options”

None.

rules."errors/through-factory" in ddd-ts-kit.config.json set to off silences the rule, and // ddd-ts-kit-disable-next-line errors/through-factory -- <reason> silences one line, exactly as for ddd-ts-kit check.

Limits

Section titled “Limits”
  • An error class is known by where it is imported from: a class declared elsewhere than domain/errors/ is not seen (naming/suffix keeps errors there).
  • The errors of the kit (NotFoundError, InvariantViolation, ValidationError...) are each one refusal with a fixed code and stay built with new.
  • Nothing is fixed: which factory replaces a constructor is a decision. ddd-ts-kit error-factories writes the plan of a migration and applies it.

With the CLI checker

Section titled “With the CLI checker”

Held by this plugin alone: the checker lists the rule and judges nothing. The compiler refuses the same thing once the class extends ConceptError, whose constructor is protected.