example_validatable_slice_test.go

package validation_test

import (
	"context"
	"fmt"

	"github.com/muonsoft/validation"
	"github.com/muonsoft/validation/it"
	"github.com/muonsoft/validation/validator"
)

type Company struct {
	Name    string
	Address string
}

type Companies []Company

func (companies Companies) Validate(ctx context.Context, validator *validation.Validator) error {
	violations := validation.ViolationList{}

	for i, company := range companies {
		err := validator.AtIndex(i).Validate(
			ctx,
			validation.StringProperty("name", company.Name, it.IsNotBlank()),
			validation.StringProperty("address", company.Address, it.IsNotBlank(), it.HasMinLength(3)),
		)
		// appending violations from err
		err = violations.AppendFromError(err)
		// if append returns a non-nil error we should stop validation because an internal error occurred
		if err != nil {
			return err
		}
	}

	// we should always convert ViolationList into error by calling the AsError method
	// otherwise empty violations list will be interpreted as an error
	return violations.AsError()
}

func ExampleValid_validatableSlice() {
	companies := Companies{
		{"MuonSoft", "London"},
		{"", "x"},
	}

	err := validator.Validate(context.Background(), validation.Valid(companies))

	if violations, ok := validation.UnwrapViolationList(err); ok {
		for violation := violations.First(); violation != nil; violation = violation.Next() {
			fmt.Println(violation)
		}
	}
	// Output:
	// violation at "[1].name": "This value should not be blank."
	// violation at "[1].address": "This value is too short. It should have 3 characters or more."
}