{
  "id": "api/forms/NG_VALIDATORS",
  "title": "NG_VALIDATORS",
  "contents": "\n\n<article>\n  <div class=\"breadcrumb-container\">\n    <div class=\"breadcrumb\">\n      <script type=\"application/ld+json\">\n        {\n          \"@context\": \"http://schema.org\",\n          \"@type\": \"BreadcrumbList\",\n          \"itemListElement\": [\n            { \"@type\": \"ListItem\", \"position\": 1, \"item\": { \"@id\": \"https://angular.io//api\", \"name\": \"API\" } },\n            { \"@type\": \"ListItem\", \"position\": 2, \"item\": { \"@id\": \"https://angular.io/api/forms\", \"name\": \"@angular/forms\" } },\n            { \"@type\": \"ListItem\", \"position\": 3, \"item\": { \"@id\": \"https://angular.io/api/forms/NG_VALIDATORS\", \"name\": \"NG_VALIDATORS\" } }\n          ]\n        }\n      </script>\n        <a href=\"/api\">API</a> > <a href=\"api/forms\">@angular/forms</a>\n    </div>\n    <div class=\"github-links\">\n  <a href=\"https://github.com/angular/angular/edit/master/packages/forms/src/validators.ts?message=docs(forms)%3A%20describe%20your%20change...#L55-L54\" aria-label=\"Suggest Edits\" title=\"Suggest Edits\"><i class=\"material-icons\" aria-hidden=\"true\" role=\"img\">mode_edit</i></a>\n  <a href=\"https://github.com/angular/angular/tree/12.0.0-next.7/packages/forms/src/validators.ts#L55-L54\" aria-label=\"View Source\" title=\"View Source\"><i class=\"material-icons\" aria-hidden=\"true\" role=\"img\">code</i></a>\n</div>\n  </div>\n  \n  <header class=\"api-header\">\n    <h1 id=\"ng_validators\">NG_VALIDATORS<a title=\"Link to this heading\" class=\"header-link\" aria-hidden=\"true\" href=\"api/forms/NG_VALIDATORS#ng_validators\"><i class=\"material-icons\">link</i></a></h1>\n    \n    <label class=\"api-type-label const\">const</label>\n    \n    \n    \n  </header>\n  \n  <aio-toc class=\"embedded\"></aio-toc>\n\n  <div class=\"api-body\">\n    \n  <section class=\"short-description\">\n    <p>An <code><a href=\"api/core/InjectionToken\" class=\"code-anchor\">InjectionToken</a></code> for registering additional synchronous validators used with\n<code><a href=\"api/forms/AbstractControl\" class=\"code-anchor\">AbstractControl</a></code>s.</p>\n\n    \n  </section>\n  \n  \n  \n  <code-example language=\"ts\" hidecopy=\"true\" class=\"no-box api-heading\">\n  const <a href=\"api/forms/NG_VALIDATORS\" class=\"code-anchor\">NG_VALIDATORS</a>: <a href=\"api/core/InjectionToken\" class=\"code-anchor\">InjectionToken</a>&#x3C;(Function | <a href=\"api/forms/Validator\" class=\"code-anchor\">Validator</a>)[]>;\n  </code-example>\n\n  \n<section class=\"see-also\">\n  <h2 id=\"see-also\">See also<a title=\"Link to this heading\" class=\"header-link\" aria-hidden=\"true\" href=\"api/forms/NG_VALIDATORS#see-also\"><i class=\"material-icons\">link</i></a></h2>\n  <ul>\n  \n    <li><p><code><a href=\"api/forms/NG_ASYNC_VALIDATORS\" class=\"code-anchor\">NG_ASYNC_VALIDATORS</a></code></p>\n</li>\n  </ul>\n</section>\n\n\n  \n  \n\n  \n<section class=\"usage-notes\">\n  <h2 id=\"usage-notes\">Usage notes<a title=\"Link to this heading\" class=\"header-link\" aria-hidden=\"true\" href=\"api/forms/NG_VALIDATORS#usage-notes\"><i class=\"material-icons\">link</i></a></h2>\n  <h3 id=\"providing-a-custom-validator\">Providing a custom validator<a title=\"Link to this heading\" class=\"header-link\" aria-hidden=\"true\" href=\"api/forms/NG_VALIDATORS#providing-a-custom-validator\"><i class=\"material-icons\">link</i></a></h3>\n<p>The following example registers a custom validator directive. Adding the validator to the\nexisting collection of validators requires the <code>multi: true</code> option.</p>\n<code-example language=\"typescript\">\n@<a href=\"api/core/Directive\" class=\"code-anchor\">Directive</a>({\n  selector: '[customValidator]',\n  providers: [{provide: <a href=\"api/forms/NG_VALIDATORS\" class=\"code-anchor\">NG_VALIDATORS</a>, useExisting: CustomValidatorDirective, multi: true}]\n})\nclass CustomValidatorDirective implements <a href=\"api/forms/Validator\" class=\"code-anchor\">Validator</a> {\n  validate(control: <a href=\"api/forms/AbstractControl\" class=\"code-anchor\">AbstractControl</a>): <a href=\"api/forms/ValidationErrors\" class=\"code-anchor\">ValidationErrors</a> | null {\n    return { 'custom': true };\n  }\n}\n</code-example>\n\n</section>\n\n\n\n  </div>\n</article>\n\n<!-- links to this doc:\n - api/forms\n - api/forms/CheckboxRequiredValidator\n - api/forms/EmailValidator\n - api/forms/FormsModule\n - api/forms/MaxLengthValidator\n - api/forms/MinLengthValidator\n - api/forms/NG_ASYNC_VALIDATORS\n - api/forms/PatternValidator\n - api/forms/ReactiveFormsModule\n - api/forms/RequiredValidator\n - api/forms/Validator\n - guide/form-validation\n-->\n<!-- links from this doc:\n - /api\n - api/core/Directive\n - api/core/InjectionToken\n - api/forms\n - api/forms/AbstractControl\n - api/forms/NG_ASYNC_VALIDATORS\n - api/forms/NG_VALIDATORS#ng_validators\n - api/forms/NG_VALIDATORS#providing-a-custom-validator\n - api/forms/NG_VALIDATORS#see-also\n - api/forms/NG_VALIDATORS#usage-notes\n - api/forms/ValidationErrors\n - api/forms/Validator\n - https://github.com/angular/angular/edit/master/packages/forms/src/validators.ts?message=docs(forms)%3A%20describe%20your%20change...#L55-L54\n - https://github.com/angular/angular/tree/12.0.0-next.7/packages/forms/src/validators.ts#L55-L54\n-->"
}