# match

> Value must equal a sibling control. The classic 'confirm password' validator — pass the sibling's name.

Source: https://ngwr.dev/reference/validators/match  
Kind: Validator

## Live demo

## Usage

```angular-ts
import { FormControl, FormGroup } from '@angular/forms';
import { WrValidators } from 'ngwr/validators';

const form = new FormGroup({
  password: new FormControl(''),
  confirm:  new FormControl('', [WrValidators.match('password')]),
});
```

## Why ngwr provides this

Cross-field equality (password confirmation) is awkward with built-ins — every project ends up hand-writing the same group-level validator. This one reads the sibling control by name.

## It cannot see a mismatch that was there from the start

A control runs its validators inside its own constructor, before it has been attached to a parent — so the sibling lookup finds nothing and this returns null, and joining the group does not re-run it. `formControlName` revalidates when it binds, so a form rendered through the reactive-forms directives corrects itself on its first change detection. The window is open for whatever reads validity FIRST — a route guard or resolver checking `form.valid`, a form built and submitted from a service, a unit test. Put `matchFields` on the group to close it and keep this one on the child for the per-field message; they use different error keys and do not conflict.

## API

| Name | Description | Type | Default |
| --- | --- | --- | --- |
| `signature` | Factory — call with the sibling control name. | `(name: string) => ValidatorFn` | `—` |
| `lookup` | Looks up the sibling via `control.parent.get(name)`. Returns null when the parent or sibling is missing. | `—` | `—` |
| `error key` | On mismatch: `{ match: { target: 'password' } }`. There is no empty guard — a filled value against an empty one reports. | `{ match: { target } }` | `—` |
| `initial values` | Cannot report a mismatch until something revalidates the control — a control runs its validators before it has a parent, so the sibling lookup finds nothing. `formControlName` revalidates when it binds; a guard or a service reading `form.valid` first does not. Put `matchFields` on the group to close that window. | `—` | `—` |

## See also

- [matchFields](https://ngwr.dev/reference/validators/match-fields) — The group-level counterpart — reports a mismatch that was there from the start.
- [wr-input](https://ngwr.dev/reference/components/input) — Password + confirm fields this rule usually guards.
- [wr-form-field](https://ngwr.dev/reference/components/form-field) — Label / hint / error scaffolding for the pair.