Very often it feels like - yes its totally clear and so easy - when watching videos like this. Then we go back to work and in most cases our problems are more complex and they still need some time to get around that barrier in the head and apply what we just have learned. I tought myself the generic stuff by using it in my daily work and I still keep watching videos like this to learn about the very edgew cases - the smart little things I missed in the documentation documents in the web.
I just had completed the rust book and searching for the term "generics" on youtube, came across this video( just for second perspective to make the thing really sink in) nailed it!
The type system in TypeScript is so much more expressive than other languages. It has great inferencing, keyof for derived types, even ternaries for narrowing/filtering types
@@ElektrykFlaaj no it doesn't, i've coded in both languages for years and I can tell you typescript's type system is way more complex for obvious reasons. I love rust tho 😇
I needed more info on generics and I had already signed up for the react course on webdev. I'm glad I purchased the course on typescript. The extra info in your course was exactly what I needed to guide me through a basic understanding of generics.
This video is a great introduction to generics! Generics can be a confusing topic, but this video breaks it down into clear and easy-to-understand concepts. I especially liked the way he showed how to use generics with API responses. This is a common use case for generics, and it was helpful to see how to create a generic API response type that can be reused for different API endpoints.
I'm currently learning Typescript and struggled a lot getting used to the syntax and trying to figure out what must be passed in to remove all these errors even though the code is correct with plain react/javascript. Thanks Kyle, this will assist me tremendously going forward.
I have not started watching this but when I saw the video, I said if I don’t understand this concept after watching your videos then I can never understand it from anywhere else. Already seeing positive comments so 😅fingers crossed 🤞
Very good introduction. One thing I would recommend for people just starting to learn this, do not even start naming generic parameters with single letters, be expressive. You may start out with a simple type where it's clear what 'T' is, but after a few weeks it has T, R, E, O and W. And a month later you have no idea any more what each of the letters are supposed to mean.
Its a better practice to name your generic arguments prefixed with T, like TModel, TRequest, etc. like we do in C#. Yes it's Hungarian-like but it works well to distinguish generic arguments while keeping them explicit and descriptive.
great video! finally got a better idea on how generics work. I had the basic notion but never understood them like this. They are kinda placeholders for a type(s).
Short question about generics. When I have this type: export type TExtensionConfig = { oExtClass: TExt; oExtConfig?: ConstructorParameters[1]; }; How look's the array type for this? Background. I woul'd like to have a settings object who have a property "aExtensions". Each extension object should have a property called "oExtClass" for defining the extension class and an optional property called "oExtConfig". Each array item can have another extension / another generic class. The extension class is a abstract. Thanks.
Hey @kyle, That is an awesome video. I wanted to point something in your last example regarding object. The value of new Date() would resolve to `object` so that might not work well. I think a more robust definition for an object would be Record or something along those lines. What are your thoughts? And thanks once again for another great video.
At 4:02, you pass to tell it what the generic value passed in should be. Makes sense. At 4:37, you seem to be passing in... the return type? querySelector, now input is of type HTMLInputElement. so which is it, the type passed in or a return type?
If you pause at 4:42, you can see that the generic is placed after the semicolon, meaning the return type. At 4:02, Kyle specifically use the generic for the parameter passed in. So it can be both. It is just a matter of how and where you define it
The generic type can be used anywhere in the function, either in the input arguments, the return type, or even both. For example: function foo(a: T) { return "foo" } function bar(a: T): T { return a } function getFoo(obj: { foo: T }): T { return obj.foo }
bro, you just explained it so well! Now I don't hate generics that much. My only issue was that for some reason you need to put generics between the name and the parenthesis. I was trying to use it for svelte 5 props and was doing: let {name} = $props() and had no idea why it wasn't working. fyi you need to do it $props()
I think that choice came from other C-family languages that also use the same syntax for generics, like C# and Java to make it more approachable and intuitive for those developers. But for someone that hasn't worked with strongly typed languages in the past, they are understandably intimidating
Is Typescript really necessary? I have not wrapped my head around why there is a use to make code more complex just to make sure you are using the correct type of variables. I mean... I know what my variables are intended to be when I create them and when I use them later. So I'm not sure of the whole point of TS.
Thank you very very much for this tutorial! Can you please make a video about differences between Generics and Interfaces? I am pretty new and if someone would ask me to define a type of something, my mind thinks "Interface" at once!
Its weird, because one syntax function foo(n: string) says "this function will accept this kind of thing, which makes sure you only pass this kind of thing" while the other function foo(n:T) says "this function takes anything, but that anything is now consistent". The second one wont stop you from sending "apples" to function checkBankAccountBalance(n:T), so it seems counterproductive.
The point of a generic is to define a relation between two or more things. For example a return type T of a function being the same as its argument type T. In your example the generic only applies to one thing, so it doesn’t define a relationship between anything.
I don't know man. I would say that it gonna use extends a lot when using generics... Every time I neede an explicit generic, half of time is with extends... Great video by the way...
Top. I'm to this day shocked how little attention people give to TS given that we use it everywhere in the professional world. Learning as much of it as possible can make a developer go a long way. The same goes for writing tests.
8:00 no no, it is smart enough to force you to put the Generic Type there. If it automatically generated / inferred types there, Generic Type would be useless there: no validation errors, it works as 'any' type all the way :)). They need Generic Type to acknowledge that what type you want to validate "data"
With (string | number)[] you said, when the type returned from getFirstElement was “string | number”: “But TypeScript is not smart enough to know that (what we passed in was actually a string).” It’s not that TS is not smart enough. It was that the type was explicitly set as “string | number”, and since the function has not actually been run yet, there is no way TS could possibly know that, no matter how smart it was. It was simply respecting the programmer’s wishes, not being stupid. 😄
![[#2024MAMA] BIGBANG (빅뱅) - 뱅뱅뱅 (BANG BANG BANG) + FANTASTIC BABY | Mnet 241123 방송](http://i.ytimg.com/vi/EQsYfiPR9uM/mqdefault.jpg)
Very often it feels like - yes its totally clear and so easy - when watching videos like this.
Then we go back to work and in most cases our problems are more complex and they still need some time to get around that barrier in the head and apply what we just have learned.
I tought myself the generic stuff by using it in my daily work and I still keep watching videos like this to learn about the very edgew cases - the smart little things I missed in the documentation documents in the web.
Whenever I find it very hard to grasp a concept, I run to this channel. You are the GOAT
This is the shortest and best explanation generic types and functions I've ever saw
Shortest, you sure?
This is shortest and the best explanation of generics in TS. Thanks for this Kyle.
Excellent, you honored the "simplified" to your name with this video, really easy to understand this way
I was baffled by Generics in the docs & other tutorials. This is incredibly helpful and clear. Thank you.
I just had completed the rust book and searching for the term "generics" on youtube, came across this video( just for second perspective to make the thing really sink in) nailed it!
He is really a Beast at explanations. Making complex things simple and crisp.
You are really doing a great job bro. Keep doing it for us.
The type system in TypeScript is so much more expressive than other languages. It has great inferencing, keyof for derived types, even ternaries for narrowing/filtering types
You need an expressive type system to support types in a dynamic scripting language.
@@arshiagholami7611actually not, for example python type system is very basic.
@@oscarljimenez5717 python doesn't have a type system. it's a type hint for your IDE.
@@arshiagholami7611 Rust has even more expressive type system than TS, and it's a static typed language
@@ElektrykFlaaj no it doesn't, i've coded in both languages for years and I can tell you typescript's type system is way more complex for obvious reasons. I love rust tho 😇
Probably the best video for generics in youtube. Hats of man.
is it a joke?
@@true227 Why do you think its a joke? Simple explanation.
Really need your nextjs course, Kyle!!!
I needed more info on generics and I had already signed up for the react course on webdev. I'm glad I purchased the course on typescript. The extra info in your course was exactly what I needed to guide me through a basic understanding of generics.
brief and get to the point, really appreciated
You are the one of the teacher who I know in RUclips , I did not understand until I watched this video why we needs typescript
This video is a great introduction to generics! Generics can be a confusing topic, but this video breaks it down into clear and easy-to-understand concepts. I especially liked the way he showed how to use generics with API responses. This is a common use case for generics, and it was helpful to see how to create a generic API response type that can be reused for different API endpoints.
Nice clear explanation - so many people get tied up in knots trying to explain generics.
Simply the best explanation of TypeScript generics out there. Kyle, you're a legend. Thanks for making these videos 🙏🏻
The best drops of knowledge in video I ever seen! Congratulations, man! And thank you very very much
short and concise, i always come back to refresh my memory
I enjoyed this. Thanks for clarifying. I actually use this but never knew I was implementing a generic type system.
Learnt new stuff today.
Wow, this is the first time I feel like I understand what Generics type is. BIG THANK YOU!
Wow this actually exactly what I need to clean up some messy types in my current project.
I'm currently learning Typescript and struggled a lot getting used to the syntax and trying to figure out what must be passed in to remove all these errors even though the code is correct with plain react/javascript. Thanks Kyle, this will assist me tremendously going forward.
I have not started watching this but when I saw the video, I said if I don’t understand this concept after watching your videos then I can never understand it from anywhere else. Already seeing positive comments so 😅fingers crossed 🤞
Very good introduction. One thing I would recommend for people just starting to learn this, do not even start naming generic parameters with single letters, be expressive. You may start out with a simple type where it's clear what 'T' is, but after a few weeks it has T, R, E, O and W. And a month later you have no idea any more what each of the letters are supposed to mean.
Its a better practice to name your generic arguments prefixed with T, like TModel, TRequest, etc. like we do in C#. Yes it's Hungarian-like but it works well to distinguish generic arguments while keeping them explicit and descriptive.
Hungarian-like. What does that even mean?
@@ivan.jeremic Hungarian notation.
Marking your type in TS with T, makes code messy IMO.
I just realised how much i needed this video. Good work.
This was great, now I need to understand when you get to that point where you see stuff like T extende keyof K or something like that
Just an amazing 12 minutes of content. Thank you so much
Thank you so much, your explanation was really easy and helpful!
Man, after watching all kinds of your videos I am now convinced you are the one to explain the monads!
Monads are easy but often over complicated. ruclips.net/user/shortsC2-ljnsckrs?si=cHTDnp5xmdRE_b9f
Goodness me, and you're not even cutting the video every time! Cheers, mate!
best webDev channel. Thanks)
I like thinkin of generics as just a way to pass in types to a function or another type. kinda like how you’d pass in parameters to a function.
great video! finally got a better idea on how generics work. I had the basic notion but never understood them like this. They are kinda placeholders for a type(s).
Short question about generics.
When I have this type:
export type TExtensionConfig = {
oExtClass: TExt;
oExtConfig?: ConstructorParameters[1];
};
How look's the array type for this?
Background. I woul'd like to have a settings object who have a property "aExtensions".
Each extension object should have a property called "oExtClass" for defining the extension class and an optional property called "oExtConfig".
Each array item can have another extension / another generic class.
The extension class is a abstract.
Thanks.
Love to see you simplifying the crazy webdev today everything build on top of everything. This mess starts to kill me.
Hey @kyle,
That is an awesome video.
I wanted to point something in your last example regarding object. The value of new Date() would resolve to `object` so that might not work well. I think a more robust definition for an object would be Record or something along those lines. What are your thoughts?
And thanks once again for another great video.
Very good! Thanks! Could you cover how I can use types, interfaces, enums to replace the JavaScript constants during code migration
Great video so far! Thanks Kyle as always! 👍
Thank you very much for always simplifying very well this kind of typescript concepts :D
Think of generics like functions for types, the generic takes a type as an argument. Once you think of it like that… it’s easy
brother your next level thankyou for all these
so amazing! it's really easy to understand 😄
You really do the web dev simplified!!!😀
Great video kyle, Please cover keywords like Infer, As and Satisfy in Typescript. Thank you.
Cool thumbnail. That was the exact emotions I was going through before seeing this video :) Thank you for the video
Easy explanation ,Simplified the explanation of generic type easy to understand.
Nicely explained, it just fit into my mind. Thanks.😊
Loved your explanation!!! 😁
At 4:02, you pass to tell it what the generic value passed in should be. Makes sense.
At 4:37, you seem to be passing in... the return type? querySelector, now input is of type HTMLInputElement.
so which is it, the type passed in or a return type?
If you pause at 4:42, you can see that the generic is placed after the semicolon, meaning the return type.
At 4:02, Kyle specifically use the generic for the parameter passed in.
So it can be both. It is just a matter of how and where you define it
The generic type can be used anywhere in the function, either in the input arguments, the return type, or even both. For example:
function foo(a: T) { return "foo" }
function bar(a: T): T { return a }
function getFoo(obj: { foo: T }): T { return obj.foo }
bro, you just explained it so well! Now I don't hate generics that much. My only issue was that for some reason you need to put generics between the name and the parenthesis. I was trying to use it for svelte 5 props and was doing: let {name} = $props() and had no idea why it wasn't working. fyi you need to do it $props()
I think that choice came from other C-family languages that also use the same syntax for generics, like C# and Java to make it more approachable and intuitive for those developers. But for someone that hasn't worked with strongly typed languages in the past, they are understandably intimidating
Great video! 👏I have been working with typescript for 3 years (angular) and I didn't even know this generic types possibilities.
Thank you for clarifying this!
Amazing! Clear and helpful
Is Typescript really necessary? I have not wrapped my head around why there is a use to make code more complex just to make sure you are using the correct type of variables. I mean... I know what my variables are intended to be when I create them and when I use them later. So I'm not sure of the whole point of TS.
JSDocs is a good alternative if you feel that way
This is super useful for writing clean Typescript code. Thanks for sharing!
Great content, well explained.
Amazing video... Really helpful!!
Thank you very very much for this tutorial! Can you please make a video about differences between Generics and Interfaces? I am pretty new and if someone would ask me to define a type of something, my mind thinks "Interface" at once!
great explanation!
Already good with generics, this is a decent coverage of them.
Great tutorial. Your explanation is awesome.
thank you a much, I love your courses
Ahh generics.... My worst enemy
Right next to regular expressions, no doubt 😉
@@joe-skeenchatgpt used to do it's magic for me on regex
I feel u
Same to you
@@unleash-gamplay dw bro practice makes perfect
Typescript generics explained well
Its weird, because one syntax
function foo(n: string)
says "this function will accept this kind of thing, which makes sure you only pass this kind of thing"
while the other function
foo(n:T)
says "this function takes anything, but that anything is now consistent".
The second one wont stop you from sending "apples" to function checkBankAccountBalance(n:T), so it seems counterproductive.
The point of a generic is to define a relation between two or more things. For example a return type T of a function being the same as its argument type T. In your example the generic only applies to one thing, so it doesn’t define a relationship between anything.
@@stevezelaznik5872 makes sense.
Thanks a lot for this!
Very helpful, Thanks
Informative but i got confused at the end
Thank you so much, I really appreciate it :)
You sir, are a hero
Any video that shows all the keyboard typing shortcuts, many of which were used here and went over my head?
Best Generics explain one of!
it was so fun to watch this
I don't know man. I would say that it gonna use extends a lot when using generics... Every time I neede an explicit generic, half of time is with extends... Great video by the way...
perfect , and thanks bro
Thanks for making it happen, do you do blazor, any content references?
Super informative video thanks 👍
Coming from C++, I love everything about TypeScript
Thank you! You know how to explain
My favorite part of this video was learning that I've already been using Generics everywhere and had no idea that's what they were called.
Would love to see a video about what stuff makes typescript’s inference not work
Brilliant video, as usual
long time no see Kyle, as always great content. 👍👍👍
very good stuff, thanks!
Thank you, brother :)
Great video, thanks for kyle
really good explanation
Top. I'm to this day shocked how little attention people give to TS given that we use it everywhere in the professional world. Learning as much of it as possible can make a developer go a long way. The same goes for writing tests.
Great video!
Never used this, but it seems useful.
Thanks!
see this is good because it's not some vague opinion piece on how types are better than interfaces or some nonsense. exclusively stuff like this pls.
So good. Ty!
Rally good one .. Keep it up..!!
8:00 no no, it is smart enough to force you to put the Generic Type there.
If it automatically generated / inferred types there, Generic Type would be useless there: no validation errors, it works as 'any' type all the way :)).
They need Generic Type to acknowledge that what type you want to validate "data"
great simplification
With (string | number)[] you said, when the type returned from getFirstElement was “string | number”:
“But TypeScript is not smart enough to know that (what we passed in was actually a string).”
It’s not that TS is not smart enough. It was that the type was explicitly set as “string | number”, and since the function has not actually been run yet, there is no way TS could possibly know that, no matter how smart it was. It was simply respecting the programmer’s wishes, not being stupid. 😄
Very helpful ❤