EZ4: Validation

The Validation contract defines composable validation services for your application. It uses EZ4's reflection system to analyze your validation handler, variables, and connected services, then generates runtime bindings required to validate inputs and enforce schemas.

Getting started

Install

npm install @ez4/validation -D

Create a validation service

Validation services are ideal for reusable schema enforcement, input sanitization, and domain‑specific validation logic that can be injected into any other contract.

import type { Environment, Service } from '@ez4/common';
import type { Validation } from '@ez4/validation';

// MyValidation declaration
export declare class MyValidation extends Validation.Service<MyService> {
  handler: typeof validateInput;

  variables: {
    myVariable: Environment.Variable<'MY_VARIABLE'>;
  };

  services: {
    otherService: Environment.Service<OtherService>;
    variables: Environment.ServiceVariables;
  };
}

Handle validation

EZ4 injects all variables and services, then invokes your validation handler with the input and schema.

// MyValidation handler
export function validateInput(input: Validation.Input, context: Service.Context<MyValidation>) {
  const { otherService, variables } = context;

  // Access injected services
  otherService.call();

  // Access injected variables
  variables.myVariable;

  // Access validation value
  input.value;

  // Access validation schema
  input.schema;
}

Use validation

Any handler with access to the validation service can perform validation.

import type { Service } from '@ez4/common';
import type { MyValidation } from './validation';

// Any other handler that has injected MyValidation service
export async function anyHandler(_request: any, context: Service.Context<DummyService>) {
  const { myValidation } = context;

  // Perform validation
  myValidation.validate({
    foo: 'foo',
    bar: 123
  });
}

This makes it easy to centralize and reuse validation logic across your application.

With your validation service defined, EZ4 handles injection, execution, and schema wiring automatically according to your contract.

Examples

• Schedule manager
• Aurora RDS CRUDL

License

MIT License