Simple Validated DTO

A self-closing (immutable via freeze), self-building (pass the input, no need to design the class), self-validating (via zod) Data Transfer Object implementation for JavaScript projects.

Reasons

• There are (older) projects where TypeScript can not be used, where validation schemas already exists, the project evolving rapidly (large team) or there are shared schemas across services/modules/functions already.
• The nature of JavaScript itself (the lack of private and protected functions)
• Validation requirements (data immutability, guarantee of data structure, etc...)

Features

• Minimal dependency (zod, vitest)
• Easy to use
• JavaScript support without overhead
• Support both require and import (ESM/CommonJs)

Requirements

• Node.js v20+
• Basic Zod schema knowledge

Usage

Import the dependencies:

  npm install @huncyrus/simple-validated-dto

See the example file.

Import the SimpleValidatedDto:

  import { z } from 'zod';
  import { SimpleValidatedDto } from '../src/SimpleValidatedDto.js';
  // Alias can be used also
  // import { SimpleValidatedDto as dto } from '../src/SimpleValidatedDto.js';

Create a schema, based on an input or data structure, example:

  const myDataInput = {
    id: 42,
    title: 'Ministry of Silly Walks',
    other: '',
  };
  // schema example
  const exampleSchema = z.object({
      id: z.number(),
      title: z.string().min(1),
      other: z.union([z.string(), z.number()]),
  });

Then pass the data and schema:

  const dto = new SimpleValidatedDto(exampleInput, exampleSchema);

Retrieve data from DTO

 console.log('Data from DTO: ', dto.data);

Note: alternatively, use the input fields as dto.<field-name> to retrieve its value

Mutate via build

The DTO provides a method to mutate the data, which shall create a new object instead of mutation:

  const newDto = SimplevalidatedDto.build(newInput, schema);

Tests

The DTO uses vitest for unit tests:

  npm run test

Test Coverage

Test coverate via Vitest:

  npm run test:coverage

Tests via docker

Build the container:

  docker build -t simple-validated-dto-tests .
  # or rebuild
  # docker build --no-cache -t simple-validated-dto-tests .

Then run the container:

  docker run --rm simple-validated-dto-tests

Author

Author: Györk Bakonyi

Contribution

Contributing rules

References

• Zod
• Vitest