Input Signals in Angular 17.1 - How To Use & Test

Learn more about RxDB - bit.ly/rxdb 🚀
The introduction of Input Signals is another step towards the integration of Signals into Angular Framework Core. From this video, you will learn how to migrate your angular components to input signals smoothly and how to adjust your unit tests. Besides that, you will know how to make your inputs reactive even before Angular 17.1. If you find this video useful, you can support my channel by sharing it with your colleagues. Thank you :)
🔥 My course Conscious Angular Testing for Beginners:
bit.ly/conscious-angular-testing
🕒 Time Codes:
00:00:00 - Intro;
00:02:02 - RxDB Sponsorship;
00:03:33 - Reactive Inputs BEFORE 17.1;
00:06:07 - Introducing Signal Inputs;
00:11:18 - How To Test Signal Inputs;
00:12:24 - Final Thoughts;
00:13:47 - Outro;
🔗 Source code from the tutorial:
github.com/DMezhenskyi/angula...
💡 Short Frontend Snacks (Tips) every week here:
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[@DecodedFrontend]

Learn more about RxDB - bit.ly/rxdb 🚀

[@Mego4884]

The database looks useful. From what I have observed the basic free functionality isn't IndexedDB database as promoted but only the in memory storage - which is not persistent. Am I getting it right or is it some misunderstanding? Thank you in advance :)

[@bobkelso5681]

@@Mego4884 RxDB has the dexie.js storage which is for free and also stores data in indexeddb

[@DecodedFrontend]

@@Mego4884 from what I understand, the free version utilizes Dexie.js RxStorage which is a minimal wrapper around IndexedDB. The IndexedDB RxStorage is a more advanced and performant plugin that’s unfortunately, a paid option. rxdb.info/rx-storage-dexie.html

[@joemtz8478]

Angular is looking better and better

[@DecodedFrontend]

Absolutely!

[@asakurayoh3909]

Angular is so much better when it comes to complex, large applications. Now with all these new features, it's killing it. The more I learn about these new features the more I'm in love with Angular ❤

[@wissamfehmi5814]

Angular Team knows who works with Angular will stick to it so they are attracting other developers since v14 by making it more similar to other frameworks but of course better 😊 As usual thank you for the fulfilled informative video

[@rakhimjonrustamov5148]

Good point!

[@gtkall]

This is a very welcome simplification effort from the Angular team. The code is simple and concise. I look forward to testing the update on my own!

[@DecodedFrontend]

I am pretty sure you will like it ;)

[@Aliakbaresmaeiliiii]

thank you man Im a Angualr developer over 7 year but every time i learning new stuff from you thank you very much man god bluss you

[@pavlokozachuk555]

What is your opinion about HttpClient and its methods? How do you see having its returned values as Observables and some Signals? What is the best way to combine values from API (Observables) with Signals in the component?

[@kevinsuarezguzman302]

I just needed the testing part, what a good explanation.

[@DecodedFrontend]

Glad to hear that it was helpful :)

[@gagiksimonyan3782]

Your videos are always useful, Dmytro) Thank you very much

[@matiassantiago4205]

great video. thanks!

[@miklosbecsei8128]

Thanks for the video! Especially the testing part helped a lot! 🙂

[@DecodedFrontend]

You are welcome! :) Glad it was helpfull ✌️

[@IAmWeirdForNG]

Thank you for this simply great content 👍 Short and concise 🔥 I benefit greatly from your videos - keep it up 👣

[@DecodedFrontend]

That's cool! Thanks for your feedback;)

[@rakhimjonrustamov5148]

Nice recommendations at the end of the video!

[@ansaganie]

Your videos make me love Angular)) Thanks!

[@DecodedFrontend]

That is so cool to hear that! Thank you for your feedback. It motivates me to make even more videos 🙌

[@jakubdrewniak2668]

quality content as always. I need to get back to it when our team migrate to ng17

[@DecodedFrontend]

I wish you a smooth migration ;)

I hope you still have those nice plants, I miss them. 😀 Keep up the good work, I like your videos.

[@DecodedFrontend]

Hey 👋🏻 Unfortunately, I had to give away them to other careful people ☹️

[@user-dy5zv2rp9x]

Спасибо! Лайк не глядя

[@innocentmazando3808]

I knew I would learn something here :). Learnt about the transformation and testing just now :)

[@vOnez212]

Nice! Thanks for sharing.

[@maksymbykov]

Thank you 💛💙

[@frbs]

Thank you for the great content.

[@DecodedFrontend]

Glad you like it :)

[@ievgensvichkar2643]

Good content, as usual.

[@MrEvilyogurt]

Thanks for the guide, not a fan of the new input options but i do like that we have this to use over get/set.

[@TheSysmat]

I like it with computedAsync lib

[@DecodedFrontend]

You mean probably ngx-extention library that provides computedAsync function? :)

[@TheSysmat]

@@DecodedFrontend yes

[@haroldpepete]

great video, thanks, what about ngModel replacement using model(), could we achieve the same result as input signal feature?

[@DecodedFrontend]

Hi 👋 you are welcome, Thanks for your question. I should probably clarify (and maybe create a separate dedicated video) but model() is about two-way data binding, and it is a concept that is separate from ngModel (which is directive). So ngModel won't be replaced with model(). ngModel (most probably) will be using the model() under the hood when the implementation of the template-driven forms is migrated to the signals.

[@vojislavvukovic7376]

Hello Dmytro! Nice video as always. I was looking into your Angular Forms course and I am curious about one thing - do you have examples/lessons in that course with OnPush ChangeDetectionStrategy? Ty again, there is always something to learn from your videos :)

[@DecodedFrontend]

Hi 👋🏻 thanks for your question. Actually, most of the examples in that course use the onPush change detection strategy and solve many problems that might appear in this Change Detection mode :)

[@peter3818]

Is it possible to access injected dependencies inside the transform function? Like let's say I want to combine an input property and join it with some stateful service?

[@maciek77killer]

is it correct to send observable to the child and use input signals?

[@ranjan4elex]

This is great the way you explain has always helped me. I have a question though is there a way to initialize the InputSignal in a dynamically loaded component?

[@DecodedFrontend]

Hi! Thanks for your question. I didn’t try it on exactly this use case, but I am sure it is possible. To set the input value for dynamically created component use ComponentRef.setInput() method.

[@alextimofeev8173]

Hello, somehow webstorm is not seeing those types on transform function so i am duplicating them, that is interesting because it is not and editor feature at all.

[@mrthefankyy]

why after transforming in the template user properties name and lastname are highlighted with red hints? concatUserNames function just add new field to existing object, so the name and lastName could not disappear 🤔

[@DecodedFrontend]

Hey 👋😊 Thanks for your question. Actually, the concatUserNames removes those properties because I destructure the name and lastName from the original user object, so in “...user” those properties are not included anymore. Then I return an already modified object and spread “…user” which means that the new object won't get the name and lastName property.

[@mrthefankyy]

@@DecodedFrontend Right, I just noticed that desctructering. thank you for the video and explanation!

[@ddgutierrez]

Hola espero que estes muy bien! Una consulta... Cuando utilizo un getter que adentro en si mismo solicita a una señal su valor y retorna el mismo. Zonejs esta escuchando si utilizo un getter? Ejemplo get nombreTipoDeCuentaSeleccionado(): string | undefined { return this.tipoDeCuentaSeleccionadaSignal()?.toString(); } Es decir. si utilizo un getter para obtener el valor de una señal. Zonejs estaria ejecutando deteccion de cambios o el getter esta desacoplado de zonejs? Saludos!

[@chinmayyogi6958]

Hi , is conditional bootstraping is possible in Angular? If yes then please make a video on how to do it. Looking forward to solution. Thanks 🙏🏻

[@DecodedFrontend]

I think I did such a video already. Please check this out - kzbin.info/www/bejne/nqObkKJ6a5V6kJYsi=hs87pitgw75slOUo

[@gund_ua]

Damn, Angular API more and more becomes inconsistent. Input signal is nice, but duplicating input metadata into it from a well known @Input decorator makes no sense to me. I'm still not using signals because most of my reactive code in rxjs and it just seems unnecessary to convert everything to signal while I can simply pipe values through async pipe lol. But great overview from you Dmytro, love it!

[@kiambojyms2196]

Js frameworks are sharing syntaxes. Computed comes from vuejs.

[@snivels]

So what is the point of signals? Is it to replace the use of ngModel two-way bindings?

[@DecodedFrontend]

Signals is the reactive primitive that has much broader area where it could be applied (not only about 2-way binding). I have a dedicated video about this topic, so you can have a look - kzbin.info/www/bejne/fnTKZKmApcuMm8ksi=AXaw0n_CUkpym6KV

[@tomasroggero6559]

How do you test outputs?? such as model()

[@TheSysmat]

But ng 17.2 model is strange for me because is bound to router

[@user-xv4ib7ks7f]

Awesome video! Maybe you know how to set input from another component? for example protected _labelRef = contentChild(LabelComponent) this._labelRef().required.set(true); not possible, because

[@user-xv4ib7ks7f]

Hello, the video is awesome! Maybe you know how to set data to input signal from another component? What do I mean, for example In LabelComponent I have InputSignal required: InputSignal = input(false); I have a parent component ParentComponent protected _labelRef contentChild(LabelComponent); and code this._labelRef().required.set(false); // it not possible because InputSignal don't have set method Maybe you know a variant to do that with signal, I know how to do that from the old way, but try to use the signal for new features, thanks a lot!

[@kasoivasoy7808]

Standalone Components + Signals almost = ReactJS&useState. Only difference is that effect() takes care of dependencies. So idk where all of these is heading to 🙃 but generally I like this approach

[@RostY]

Reactgular

[@pavlokozachuk555]

Google is preparing to be redeemed by Meta or vice versa

[@moveonvillain1080]

New to Angular and I come from React. What I take away from this video is that input signals enforce unidirectional data flow similar to how React has. Only from Parent to Child and Child cannot modify unless parent provides a method for child to modify the Input coming from parent. Am I on right track here?

[@fawzzhkz9023]

❤

[@itslen]

Is it possible to use input signals with the router?

[@DecodedFrontend]

Yes! My next video is partly about that ;)

[@itslen]

@@DecodedFrontend I’ll be waiting

[@dharmarajana3989]

We can achieve the same using behavioural subjects..why do we need signals?

[@DecodedFrontend]

Hey, Yes you can. However, signals are more lightweight alternative and will be deeper integrated into Angular framework in the future. All new features will be optimized and developed with Signals in mind when RxJS will become eventually optional. So the Signals are more future proof solution.

[@ChipepeYamamoto]

I think that subjects must be subscribed and unsubscribed and are zone js dependent. Signals in other hand do not affect the whole tree of component parent down.

[@amosisaila8416]

Maybe you could have shown how to play with withComponentInputBinding() and Signal Inputs. Btw great video.

[@DecodedFrontend]

Thank you :) It is a great idea! I'll add it to the list

[@danieldanish2453]

how to become angular dev expert ?

[@tryhuma]

do you live in Poland now?

[@DecodedFrontend]

Haha, no :) Why did you think so?😄

[@tryhuma]

@@DecodedFrontend Many Ukrainians moved to Poland after the Russian aggression. I thought about inviting you for a beer xd

[@DecodedFrontend]

@@tryhuma yeah, that’s an unfortunate true. However, I have been living in Austria for many years already. Anyway, I am always happy to meet in Vienna 😊

[@deeperton]

Breaking contracts of using decorators is so React-way... don't like it. Now you need a custom IDE tuning to highlight that input function to make it noticeable in the code.

[@user-ed8eb6cx7o]

Все добре, але чому не державною?

[@DecodedFrontend]

Дякую за коментар. Це тому, що аудиторія в багато разів менша, ніж англомовна. Плюс, більшість українців в IT сфері чудово розуміють англійську.

[@user-ed8eb6cx7o]

@@DecodedFrontend так і мову втратимо( ото такі патріоти(

[@DecodedFrontend]

@@user-ed8eb6cx7o Додам трохи контексту: цей канал не хобі, а моя основна робота. Якщо я перейду на українську, то втрачу аудиторію, що, банально кажучи, призведе до закриття каналу, бо в мене не буде ресурсів на його підтримку. І в чому сенс? Якщо у вас є бажання профінансувати канал таким чином, що мені не треба буде більше турбуватися за фінансування, то я з радістю почну робити контент українською.

[@user-ed8eb6cx7o]

@@DecodedFrontend а чому фрілансер по життю може робити контент українською і це не призводить до закриття каналу, а Ви ні? То просто у нього є бажання, а у Вас немає нажаль...але головне що флаг показали ото така підтримка української мови це такий ваш внесок і спільну боротьбу...

[@D9ID9I]

Such an awful pattern. Reminds me knockoutjs times.

[@DecodedFrontend]

Hi! Thanks for your thoughts :) By the "pattern" do you mean signals in general? If yes, I would be curious to hear why exactly? (except being similar to what KnockoutJS :) )

[@D9ID9I]

@@DecodedFrontend yeah, all these computed, observables were so absolutely unfun and clunky to work with back in a days. AngularJS was like a breeze after that. And I can't believe Angular downgrades back. What I see gives me bad vibes. Like they hired some brand new and ignorant Harvard boys who think they invented proper way 🤦‍♂