Angular Injection Context Explained

Рет қаралды 4,217

Күн бұрын

Ever wonder what an Angular injection context is? Angular's dependency injection system relies on a runtime context called the injection context. We can only use dependency injection in code that runs in that injection context.
In this video, we explain what an injection context is, examine where the injection context is available, and walk through what happens when you inject a dependency outside of the injection context. We use both constructor-based dependency injection, and the inject function introduced in Angular v16.
Links
Code: stackblitz.com/~/edit/injecti...
Documentation: angular.dev/guide/di/dependen...
Content
00:00 What is the injection context?
00:09 Dependency injection
00:35 inject() function
01:43 Injection context
02:45 Where the injection context is not available
05:11 inject() in an exported function
06:33 Wrap up
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😊About Me
Hey! I'm Deborah Kurata
I'm a software developer and KZbin content creator. I speak at conferences such as VSLive and ng-conf. I write articles for freeCodeCamp. And I'm a Pluralsight author with courses in the top 10 most popular (out of 7,000+) for over 5 years. For my work in support of software developers, I've been recognized with the Microsoft Most Valuable Professional (MVP) award, and I'm a Google Developer Expert (GDE).
View my KZbin content: / @deborah_kurata
Contact me on Twitter: / deborahkurata
Find my Pluralsight courses: www.pluralsight.com/profile/a...
Access my freeCodeCamp articles: www.freecodecamp.org/news/aut...
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Пікірлер: 45

@d13g0m0r3n0 Ай бұрын

Another awesome explanation, Deborah you're wonderful

@deborah_kurata Ай бұрын

Thank you so much! 😊

@vd2828 Ай бұрын

The content is so useful. Thank you very much.

@deborah_kurata Ай бұрын

Great to hear that. Thank you! 😊

@fahadgaliwango4502 Ай бұрын

you make angular concepts simple and easy to understand. thanks since NG2

@deborah_kurata Ай бұрын

That is wonderful to hear. Thank you so much! 😊

@omararizmendi7574 Ай бұрын

Thank you very much for this explanation. A really easy way to understand this topic, thanks.

@deborah_kurata Ай бұрын

Thank you!

@orhancanoguz4423 Ай бұрын

Thanks , Professor...

@deborah_kurata Ай бұрын

You are welcome! Hope it was useful!

@poojajagtap7349 Ай бұрын

Valuable content thanks

@deborah_kurata Ай бұрын

Thank you!

@felipemendietaz4947 Ай бұрын

Woow Deborah, I love your explanations, thanks a lot, I came here for your free code camp tutorial about signals. Greetings from Ecuador.

@deborah_kurata Ай бұрын

Greetings! So great to hear the videos are helpful. Thanks! 😊

@osamaabozahra Ай бұрын

Thanks Deborah, you're my favorite teacher great video, waiting for the new one, preferably an advanced one 😀

@deborah_kurata Ай бұрын

That is so kind of you to say! Thank you! When you say "advanced", do you have something specific in mind?

@osamaabozahra Ай бұрын

@@deborah_kurata There are multiple ones actually: - runInInjectionContext use cases - injector.create function Basically the dependcy injection advanced use cases in a practical way Also another video in my mind is one like the "RxJS in Angular: Terms, Tips, and Patterns" but for signals 😃 Thanks a lot for your videos again

@deborah_kurata Ай бұрын

@@osamaabozahra I'll definitely add those topics to my list. I do have a video on signals here: kzbin.info/www/bejne/paK8gnpthrKXsNk But I assume you're looking for something a bit more advanced? You could check out my signals play list: kzbin.info/aero/PLErOmyzRKOCrzJ9zUEGgC1zVzVGt3hMmV

@osamaabozahra Ай бұрын

@@deborah_kurata Thanks Deborah, I have already watched most of your signals playlist, and will recap them. But I meant a full video discussing some of the emerging patterns related to signals and what are the best practices using them.

@deborah_kurata Ай бұрын

I just posted a video about this today: kzbin.info/www/bejne/qHm0kmeJpcqel6M

@poojajagtap7349 Ай бұрын

Thanks Best video

@deborah_kurata Ай бұрын

Thanks so much!

@pranaykhilari7345 Ай бұрын

Thanks Deborah. What is the advantage of using inject over constructor base dependancy injection

@deborah_kurata Ай бұрын

One of the key reasons is that it is more explicit. The code is saying to inject a dependency and assign the reference to a variable. When using a constructor, you have to know the "secret" about what a constructor parameter means. And if you forget the public/private keyword, the magic doesn't happen. And, as shown near the end of the video, you can use inject in places you can't use constructor-based dependency injection.

@ritiksahu5310 8 күн бұрын

thanks

@deborah_kurata 7 күн бұрын

😊

@user-wk2ck7xi8p Ай бұрын

Something new 🎉 I haven't heard

@deborah_kurata Ай бұрын

Hope it was useful! 😊

@ruekkart Ай бұрын

Nice explanation. I came to Angular from a backend background and I loved it, especially because of its DI system. However, I'm now worried about the inject() function because, in the backend world, it is generally considered bad practice to use property injection. It is encouraged to use constructor injection most of the time, mainly to maintain better control over the dependencies of a given class/component/module. What do you think about this?

@deborah_kurata Ай бұрын

Thanks! I looked at that a bit when I was researching for this post. I came upon this, which provides some background on inject() in a JavaScript world: www.reddit.com/r/Angular2/comments/18ry9m4/the_inject_function_in_angular_is_not_just_a_toy/

@cooleboy50 Ай бұрын

Great video Deborah. What is the primary reason that we can only inject within the injection context?

@deborah_kurata Ай бұрын

Thanks! As per the docs: "The dependency injection (DI) system relies internally on a runtime context where the current injector is available. This means that injectors can only work when code is executed in such a context." angular.dev/guide/di/dependency-injection-context

@potatopower2144 Ай бұрын

Hello Deborah! Do you have any suggestions for finding a mentor? I've been learning web development solo for a year and a half now, building full stack projects using Java Spring / Angular and deploying to my AWS EC2 instance. I'm preparing my portfolio site and resume for the job hunt and have 5 decent solo projects to show.

@deborah_kurata Ай бұрын

Wow! Congratulations on building up your portfolio. Angular Spaces might be a good place to start: www.angularspace.com/. Also Angular Nation/Tech Stack Nation: techstacknation.com/

@michaelharrington5860 Ай бұрын

@@deborah_kurata Thank you so much. These are exactly what I was looking for. See you in the next video 👍

@CodingAbroad Ай бұрын

So is using constructor now undesirable? Can we avoid using constructor completely now?

@deborah_kurata Ай бұрын

Not necessarily undesirable. Yes, you can avoid using the constructor if you want to. But you can use either. Many teams are standardizing on the inject function approach. Others prefer to see the injected services all in one place in the constructor.