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doesntStartWith

Validate that a string does not start with any of the given substrings (case-insensitive).

Signature​

NguardValidators.String.doesntStartWith(...values: primitive[]): ValidatorFn
ParameterTypeDescription
...valuesprimitive[]One or more substrings — the input must start with none of them

Reactive forms​

import { FormControl } from '@angular/forms';
import { NguardValidators } from 'ng-nguard';

// Reject relative protocol URLs
const externalUrl = new FormControl('', [
    NguardValidators.String.doesntStartWith('//', '/'),
]);

Template-driven forms​

<input ngModel name="externalUrl" [nguardDoesntStartWith]="['//', '/']" />

Error key​

{ doesntStartWith: true }

Notes​

  • The check is case-insensitive.
  • Numbers and booleans are coerced to string before comparison.
  • Empty strings pass (nothing to start with).
  • If no values are supplied, validation passes (no constraint to violate).

See also​