ddd-ts-kit/schema-presentation-only

Architecture id: schema/presentation-only. Default severity: error in recommended, error in strict.

Applies to: the production files of the shared kernel and of domain/, application/, infrastructure/ and published-language/ of a context, in a project whose config says "stack.schemas": "shared".

Why

A schema says what a client sends or receives: it is a presentation type, and it changes with the HTTP contract, not with the model. The shared kernel is imported by every layer of every context, so a schema written there reaches the domain and the use cases. A schema several contexts answer with lives under presentation/ of the shared kernel, and only presentation layers import it.

Reported

• in the shared kernel outside presentation/, an import of a validation library: zod, class-validator, class-transformer, class-validator-jsonschema, valibot, arktype, TypeBox, @ddd-ts-kit/validation
• in domain/, application/, infrastructure/ and published-language/ of a context, and in the shared kernel outside presentation/, an import of a file of presentation/ of the shared kernel

Incorrect:

shared-kernel/money.ts

import { IsInt, IsString } from 'class-validator';
export class Money { @IsInt() cents = 0; @IsString() currency = ''; }

Correct:

// shared-kernel/presentation/money.schema.ts, imported by presentation layers only
import { IsInt, IsString } from 'class-validator';
export class Money { @IsInt() cents = 0; @IsString() currency = ''; }

Options

None.

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

Limits

• A validation library imported by domain/ or application/ of a context is reported by layer/domain-purity and layer/application-inward, not here. One imported by infrastructure/ is allowed: an adapter may check what a remote system answers.
• Specs are not judged.

With the CLI checker

ddd-ts-kit check holds the same rule on the text of the imports; schema/no-duplicate-shape, which compares the shapes of a context with each other and with the shared kernel, is held by the checker alone.