Reactive Forms in Angular - Dynamic Validation

Learn Everything About Angular Forms 🚀

In this video about Reactive Forms in Angular, I will show you how you can apply and remove validators to certain form controls dynamically, depending on the values from other form controls in your Angular Form. I will show you how to do that using ReactiveForms. You will see which pitfalls you might encounter while implementing this feature and, of course, I will show you how you can overcome them.

🕒 Time Codes:
00:00 - Intro
00:00:55 - Dynamic Validation in Action
00:11:27 - Promo: Advanced Angular Forms Course
00:12:53 - Outro;

💡 Short Frontend Snacks (Tips) every week here:

[DecodedFrontend]

Learn Everything About Angular Forms 🚀

[rembautimes]

The angular forms course is gold quality. I subscribed last year and helped me a lot in my development

[ferhado]

I have subscribed to the Angular Forms course. No words, it's just amazing. I highly recommend it to everyone who wants to reach an advanced level in Angular Forms.

[nedafayazi]

I wish I could like your Angular Form course million times. Thank you very much for your generusity in teaching complex issues in a very simple way.

[ferhado]

Dmytro, could you please make a video about Angular Material theming for v18? The documentation is confusing.

[DrCuttler]

Very cool! I actually did the same thing recently, but did it slightly differently:

a) I added the Validator to the field permanently but enabled and disabled them instead of added and remove them
b) I transferred the valueChanges observable into a signal and used angular effects for switching.

BTW: I really enjoy your channel! You made me a better angular developer! :)

[MateusBellomo-mlzm]

I was time travelling here, nice video.

[Nabulio]

Thank you Dmytro.
Great content.

I have a question about your course. Are you updating its content with the features of the latest versions of Angular? (17 and 18 for example)

[arwaromdhane]

I want to thank you for your gold videos you helped me a lot ❤❤❤❤❤❤❤❤

[madeOfClay]

Top quality content!
Any plans for making a course all about signals with Angular?
Thank you for the video Dmytro

[koempf]

I subscribed to this course also last year :-) great course absolutely :-) would be cool if you could update it to Angular 17/18 features :-) especially Signals :-)

[DemystifyFrontend]

You are an awesome guy, love your videos ❤️

[jeffnikelson]

Why not use new features like the new control-flow or the takeUntilDestroyed operator

[thanhtuanle]

hey, thanks for your wonderful forms course. How can i get the source code of this video to reference?

[RahafHaj]

I think using cross validation is better when control validation is related to other control values within the form, where we can get the year value from form.value.year and check it conditionally every time


AbstractControl) {
const {year, passport} = form.value;
if(year > x && !passport) {
return {passportRequired: true}
}
return null
}

[cwnhaernjqw]

Hi Dmytro nice video. Question: do we also have to unsubscribe onDestroy when subscribing to a form control, or angular takes care of that? Thanks

[vasiliykrush]

For some reason I had expected something better written than what I saw in the video. Like some util. But any case, thanks

[GamerOfBharat]

If we do updateValueAndValidity() isn’t it just call the valueChanges() again and again

[andreiarpenti]

If user selects 10 times an adult date, won't be the validator added 10 times?
Or angluar sees that the object is already there, and won't add it many times?

[marcwinner]

Is assigning that Validator reference to a local variable for minLength really the "official" way of doing it? I think it would be more cohesive to have some sort of option for it in the method call add/removeValidators. Slava Ukraini!