@leancodepl/validation

TypeScript library for handling validation errors in CQRS command responses with type-safe error code mapping.

Installation

``bash
npm install @leancodepl/validation


or


yarn add @leancodepl/validation
`

API

$3

Creates a validation error handler that processes errors with type-safe error code mapping.

Parameters:

- validationErrors: ValidationError[] - Array of validation errors to process
- errorCodesMap: TAllErrors - Mapping of error names to numeric codes
- validationResults?: TInResult[] - Optional array of previous handler results

Returns: Handler with handle, handleAll, and check methods

$3

Handles CQRS command responses and transforms them into validation error handlers.

Parameters:

- response: ApiResponse> - API response containing command result
- errorCodesMap: TErrors - Mapping of error names to numeric codes

Returns: Validation error handler with success/failure support

Usage Examples

$3

`typescript
import { handleValidationErrors } from "@leancodepl/validation"

const errorCodes = { EmailExists: 1, InvalidEmail: 2 } as const
const errors = [{ ErrorCode: 1, ErrorMessage: "Email exists", PropertyName: "Email" }]

handleValidationErrors(errors, errorCodes)
.handle("EmailExists", () => console.log("Email already registered"))
.handle("InvalidEmail", () => console.log("Invalid email format"))
.check()
`

$3

`typescript
import { handleResponse } from "@leancodepl/validation"

const errorCodes = { UserNotFound: 1 } as const
const response = await fetch("/api/users/123", { method: "PUT", body: JSON.stringify({ name: "John" }) })

handleResponse(response, errorCodes)
.handle("success", () => console.log("User updated"))
.handle("UserNotFound", () => console.log("User not found"))
.handle("failure", () => console.log("Request failed"))
.check()
`

$3

`typescript
import { handleValidationErrors } from "@leancodepl/validation"

const errorCodes = { Required: 1, Invalid: 2 } as const
const errors = [
{ ErrorCode: 1, PropertyName: "email", ErrorMessage: "Email required" },
{ ErrorCode: 2, PropertyName: "name", ErrorMessage: "Invalid name" },
]

handleValidationErrors(errors, errorCodes)
.handleAll(["Required", "Invalid"], errorGroups => {
errorGroups.forEach(({ errors }) => {
errors.forEach(error => console.log(${error.PropertyName}: ${error.ErrorMessage}))
})
})
.check()
`

$3

`typescript
import { handleResponse } from "@leancodepl/validation"

const errorCodes = { InvalidData: 1 } as const
const response = await fetch("/api/data")

const isSuccess = handleResponse(response, errorCodes)
.handle("success", () => true)
.handle(["InvalidData", "failure"], () => false)
.check({
reducer: (prev, current) => prev && current,
initialValue: true,
})
``