DTO

API Documentation

$ npm install @neatau/dto

TypeScript library that provides a foundation for defining and passing DTOs from your input layer (e.g. REST controllers, GraphQL resolvers, RabbitMQ messages, ...) into your service layer, built on top of Zod.

Problems solved:

• Clean and feature rich implementation of your DTO layer.
  • Deterministic JSON serialization.
  • Deterministic hashing.
  • Deep equality checks between DTOs.
  • Conversion to other commonly required data structures such as URLSearchParams.
• Validation and type inference via Zod.

Examples

Basic Usage

// Defines a new DTO class.
class CreateArticleDTO extends DTO({
  schema: z.object({
    title: z.string().min(3).max(300),
    body: z.string().min(25).max(2500),
    authorId: z.uuid(),
  }),
}) {
  // Other getters or DTO functionality here.
}

// Somewhere in your service layer...
async function createArticle(dto: CreateArticleDTO) {
  const { title, body, authorId } = dto.getData();

  // Store in the database, send to API, whatever.
  await database.save(Article, {
    title,
    body,
    authorId,
  });
}

// Make the call with a DTO instance.
await createArticle(
  new CreateArticleDTO({
    title: 'This is a title',
    body: 'This is the article body',
    authorId: '03da2971-ad92-4332-a757-5605864e7941',
  }),
);

Custom Errors

Provide a transformError() callback to transform any ZodErrors thrown during interaction with the DTO into your own custom error class.

class CustomErrorDTO extends DTO({
  schema: z.object({
    value: z.string().max(10),
  }),
  transformError: (zodError) => new Error('There was an error'),
}) {
  //
}