> For the complete documentation index, see [llms.txt](https://error.angular-package.dev/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://error.angular-package.dev/validationerror/constructor.md).

# ★ Constructor

## `ValidationError()`

Creates the [`ValidationError`](/validationerror/overview.md) instance that represents validation error with the [message](/commonerror/accessors/get-message.md) built of the given described [problem](#problem-string), its [solution](#fix-string), and optional explicit [identification](#id-id), on the supplied or stored error message [template](#template-string-error.template).

{% code title="validation-error.class.ts" %}

```typescript
constructor(
  problem: string,
  fix: string,
  id?: Id,
  template = ValidationError.template
) {
  super(problem, fix, id, template);
}
```

{% endcode %}

### Parameters

#### `problem:`[<mark style="color:green;">`string`</mark>](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String)

Description of the [problem](/getting-started/basic-concepts.md#problem) of a [`string`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String) type.

#### `fix:`[<mark style="color:green;">`string`</mark>](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String)

A solution to the given [`problem`](#problem-string) of a [`string`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String) type.

#### `id?:`[<mark style="color:green;">`Id`</mark>](/validationerror/generic-type-variables.md#validationerror-less-than-id-greater-than)

Optional unique [identification](/getting-started/basic-concepts.md#identification) to the given [`problem`](#problem-string) of generic type variable [`Id`](/commonerror/generic-type-variables.md#wrap-opening).

#### `template:`[<mark style="color:green;">`string`</mark>](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String)`=`<mark style="color:green;">`ValidationError`</mark>`.template`

A template of error message with the replaceable [`{problem}`](/commonerror/properties/static-template.md#problem), [`{fix}`](/commonerror/properties/static-template.md#fix) and optional [`{id}`](/commonerror/properties/static-template.md#id) tags. By default, the value is equal to the static property [`template`](/commonerror/properties/static-template.md).

## Example usage

```typescript
// Example usage.
import { ValidationError } from '@angular-package/error';

// Returns
// ValidationError: ProblemTE:201: Wrong type => Fix: Change the type
new ValidationError('Wrong type', 'Change the type', 'TE:201');
```