State pattern (TypeScript Design Patterns)

[@reveryoungfo]

Hi, are you going to continue this series? :D I think there are more patterns and you explain them in the right way! Thanks

[@sarthaksahu117]

Please make videos on more patterns! It is very easy to remember these patterns with the examples you are giving. Thanks!

[@creative-commons-videos]

Doesn't Circular Dependencies count as a bad practice ? where we require State in Order and Order in State ?

[@troglokev]

There’s a bit of a code smell here, in that the interface is forcing the implementation of methods for operations that don’t exist in the state diagram.

[@estranhokonsta]

Not really. The state diagram just show what is 'legal' to do. This pattern strength is that it can react intelligently to any possible transitions, legal or not. It doesn't make assumptions about the capacity of the UI or API to not allow illegal state transitions.

[@ChristopherOkhravi]

Great idea to exemplify Design Patterns in TypeScript! Subbed 😀

[@Cognitoman]

ohh shit guess who it is :)

[@amitpattjoshi]

@@Cognitoman just watched chris video to get the basic clear and your example just helped me to clarify further if any doubt I had. But dont agree with instanciating all concrete states in constructor seems redundent.

[@hangchen6131]

That's a great design pattern tutorial, also can be applied to all programming languages generally.

[@TheZoreslav]

The best explaining of pattern in js

[@willl0014]

Very well explained sir, and excellent example selection.

[@vooose]

great series of videos please keep them going

[@simplyexplained]

Thanks! Any patterns in particular that you would like to see explained?

[@vooose]

@Savjee I just came across these videos to learn more about TS (rather than design patterns per se) but I find the practical examples easier to learn from than videos specifically about TS language features (tho your other series on TS I still found most useful) - not exactly a design pattern but perhaps a video on TDD (or just unit testing) with TS would be helpful

[@narendratechguy7140]

Why did you stopped developing this series, please complete it

[@simplyexplained]

+narendra techguy any patterns you would like to see?

[@narendratechguy7140]

Savjee all the patterns that are in GoF

[@MrEnsiferum77]

This is bad implementation of the state pattern, the Order class, does not need to know how to create the classes who implement the state interface and also u breaking open-close principle. Also, classes who implements the state interface, are bound to particular class in this case Order. U need DI with interface, so u can swap Order class in future.

[@ojuliomiguel]

Do you have this code example with this improvements?

[@avimehenwal]

Totally agree (Y)

[@avimehenwal]

Are getters and setters required in this case? I see the class attribute is already set to public at 2:30, i am thinking when property could be directly accessed and changed from outside why have getters and setters? Do they provide any additional value which I might have overlooked? Super thanks for answering my query :)

[@simplyexplained]

Getters and setters are mainly used to allow you to change underlying structure of your classes without affecting your application itself. Setters are also useful to do validation before accepting values in your application.

[@avimehenwal]

@@simplyexplained when you say validations that makes sense. Still why have public class attributes then? Doesn't take make the attribute insecure !!! ? We can directly change it from outside using className.attribute = "new value" Doesn't that defeat the purpose of getters and setters in the first place?

[@simplyexplained]

Oops, yes, they should've been private! This is often a requirement in companies to not have any public attributes.

[@avimehenwal]

@@simplyexplained Thanks for the closure :) Have a great day

[@SportAnalysisKing]

I really liked your explanation on StatePattern it was very clear and concise. I would love to see how you implement complex if and else with Rule pattern and Decorator pattern to do logging or anything with decorator but to see logging would be nice

[@ayushpratap4726]

HI Savjee! Really liked all your design patterns videos for typescript! Would really appreciate if you will add more videos to the series! waiting for a very long time ! Please make videos on GANG OF FOUR design Patterns in typescript!

[@gbkEmilgbk]

what about circular references? Order uses CacneledOrderState, CanceledOrderState use Order - ?

[@SibyAugustine93]

Brilliant tutorial... And if we want to add some other states in future how will we do that? without disturbing current system.

[@dmytrosamburskyi1022]

You are doing great videos. But I have a remark, you don't keep object's properties encapsulated. In most places 'public' properties should be 'private', especially when you have getter and setter or pass an object into constructor. Though the series is about design patterns, it's showing bad habit pattern :)

[@simplyexplained]

You are 100% right and I normally don't make that mistake. Damn it! Thanks for letting me know. I'll put a warning up in the description!

[@okragula]

Thanks for the great series, you’ve helped me a lot. I have to ask though (at least what to google for), in the ‘Order state: ‘ log statement, what is the use of in that particular case (I understand that any means of any type, I’ve never seen it used like that.)

[@pathakvivek7865]

Please make such videos of other patterns too..

[@9324981]

Nice series.

[@fieldset3689]

Why using an state Interface instead of a state Class ?

[@DanielMunoz-bn6gk]

Hi, excellent video. I need you help, i try this pattern with angular 6 but not working, get this error: "Converting circular structure to JSON". I think this is because order have a State field and the state have a order field. Do you know how to solve this problem?

[@cedrics7374]

Hi Daniel, did you find a solution yet? I was planning on using on an Angular 8 project

[@ngneerin]

Isn't this against DRY principle

[@aeromina]

Thank you so much for these videos :)

[@awsguide2912]

Thank You a Lot !!

[@AmxCsifier]

brilliant stuff

[@tervancovan]

this is what I want

[@buchdev]

Why did you used any on line 123? Oh God! you're using typescript, use a type, please

[@NulledExp]

uff some big cycles around, please ffs TELL DONT ASK / LoD? :( I know this video is about State pattern but this can be super dangerous when you try to show how to implement design patterns when u burn the whole base of Design, PLEASE

[@AlbertoRivas13]

This guys doenst have the text editor in dark mode, dislike

[@angelhdzdev]

This guys doesn't appreciate the amount of free and clear information provided, but complains about colors, dislike