How can I create custom validators in Angular CLI?

How can I create custom validators in Angular CLI?

You can create custom validators in Angular by defining a function that returns a validation function. Would you like an example?

Yes, please provide an example of a custom validator.

Sure! Here's a simple example:

import { AbstractControl, ValidationErrors, ValidatorFn } from '@angular/forms';

export function customValidator(): ValidatorFn {
    return (control: AbstractControl): ValidationErrors | null => {
        const isValid = /* your validation logic */;
        return isValid ? null : { 'customError': true };
    };
}

You can then use this validator in your form controls.

How do I apply this custom validator to a form control?

You can apply the custom validator when creating your form group. For example:

this.form = this.fb.group({
    myControl: ['', [customValidator()]]
});

This will apply your custom validator to the 'myControl' form control.