src/app/Validators/equal-validator.directive.ts
// equal-validator.directive.ts
import { Directive, forwardRef, Attribute } from '@angular/core';
import { Validator, AbstractControl, NG_VALIDATORS } from '@angular/forms';
@Directive({
selector: '[validateEqual][formControlName],[validateEqual][formControl],[validateEqual][ngModel]',
providers: [
{ provide: NG_VALIDATORS, useExisting: forwardRef(() => EqualValidator), multi: true }
]
})
export class EqualValidator implements Validator {
constructor(@Attribute('validateEqual') public validateEqual: string,
@Attribute('reverse') public reverse: string) {
}
private get isReverse() {
if (!this.reverse) return false;
return this.reverse === 'true' ? true: false;
}
validate(c: AbstractControl): { [key: string]: any } {
// self value
let v = c.value;
// control vlaue
let e = c.root.get(this.validateEqual);
// value not equal
if (e && v !== e.value && !this.isReverse) {
return {
validateEqual: false
}
}
// value equal and reverse
if (e && v === e.value && this.isReverse) {
delete e.errors['validateEqual'];
if (!Object.keys(e.errors).length) e.setErrors(null);
}
// value not equal and reverse
if (e && v !== e.value && this.isReverse) {
e.setErrors({ validateEqual: false });
}
return null;
}
}