notPattern

Import

import { notPattern } from 'ngxtension/not-pattern';

Usage

Use notPattern to validate that a form control’s value does NOT match a specific pattern. This is the opposite of Angular’s built-in pattern validator.

import { FormControl, ReactiveFormsModule } from '@angular/forms';
import { notPattern } from 'ngxtension/not-pattern';
n;

@Component({
  selector: 'my-app',
  imports: [CommonModule, ReactiveFormsModule],
  template: `
    <input [formControl]="noNumbersControl" />
    @if (noNumbersControl.errors?.['notPattern']) {
      <div>Numbers are not allowed!</div>
    }
  `,
})
export class App {
  // Will be invalid if the input contains any numbers
  noNumbersControl = new FormControl('', notPattern(/[0-9]/));
}

Examples

// Prevent numbers in text
const noNumbersControl = new FormControl('abc', notPattern(/[0-9]/));
console.log(noNumbersControl.errors); // null - valid because 'abc' has no numbers

const withNumbersControl = new FormControl('abc123', notPattern(/[0-9]/));
console.log(withNumbersControl.errors);
// {notPattern: {disallowedPattern: '/[0-9]/', actualValue: 'abc123'}}

// Can also use string patterns
const noSpecialCharsControl = new FormControl(
  'hello',
  notPattern('[!@#$%^&*(),.?":{}|<>]'),
);

API

Inputs

• pattern: string | RegExp - The pattern that the input should NOT match. Can be either a regular expression or a string.

Error Format

When validation fails, the validator returns an error object with this structure:

{
  notPattern: {
    disallowedPattern: string, // The string representation of the pattern
    actualValue: string        // The current value that matched the pattern
  }
}

Notes

• Empty values are considered valid to allow for optional controls
• When using string patterns, the validator automatically adds ^ and $ if they’re not present
• The validator supports values that are strings, arrays, or Sets