Most of the NPM modules (major ones) uses this pattern, e.g: Mongoose. This pattern is one of the best if anyone is creating a library or something like that as you might need to output some debug information for the module. Great video thanks a lot....BTW thanks for changing your uniform
@fabriziotofanelli5 жыл бұрын
its kind weird to see this smooth explanation regarding this subject because, most of times, some teachers don't really grasp this concept and makes this even harder... great content man... keep it up =)
@WebDevSimplified5 жыл бұрын
Thanks! I really appreciate it. I always put in extra time researching and working with any technology/topic before I record a video on it even if I already know it really well, since I want to make sure I understand all the intricate details so I know which parts are the important parts I need to explain in a way that makes sense.
@fabriziotofanelli5 жыл бұрын
@@WebDevSimplified And I really appreciate your efforts to bring us the best way to absorbe, sometimes, complex subjects and break them into tiny pieces easily to understand and digest.... hope to see much more great content from you =)
@omarabid39323 жыл бұрын
Hi, The implementation looks good but In order to verify that the singleton implementation is working correctly you need to instantiate the FancyLogger twice, in your current implementation the constructor is called only once.
@Gabriel-V2 жыл бұрын
Agreed. And the export is the class itself, because whenever you run new FancyLogger(), you will get back the same FancyLogger instance. and that is handled inside the class constructor itself. If you export the logger instance created, as shown in the video, the constructor doesn't need to be changed this way
@Matter743Ай бұрын
Better use typescript instead of js and make the constructor private
@thehardyboiz15 жыл бұрын
This was pretty useful, i hope that your channel grows a lot in the next few months, you totally deserve it :)
@WebDevSimplified5 жыл бұрын
Thank you. My channel has already grown a lot the last few months. I can't imagine even more growth.
@davidfonseca6984 жыл бұрын
And now your words became real. Just last week 20 thousands people subscribe to this channel!
@julescsv70123 жыл бұрын
Sometimes I wonder where I would be without you. 🙏🙏🙏
@nabiisakhanov35224 жыл бұрын
Angular services are singleton by default, so I guess this pattern does have its niche
@user-se8hw9kn3mАй бұрын
Thanks kyle. Very well explained.
@ardhiirfansyabani49213 жыл бұрын
to the point and really understandable! love it! keep up those great contents!
@alejandroperezrivas23974 ай бұрын
damn this has to be one of the best explanations i had with this pattern.
@karthik-ex4dm4 жыл бұрын
The only video I found on youtube with 10K+ views and 0 dislikes... For a long time, I was thinking guys at youtube randomly add dislikes to videos coz there are many good videos that got dislikes for no reason...
@Deretvir Жыл бұрын
Nice explenation but... All the design patterns should be presented in TypeScript. The key words like private, public, static, protected are crucial in my opinion. On the other hand, Everyone who has the TS knowledge should handle to add TS to your's code :) Thank You!
@klauspetersen85934 жыл бұрын
Why export an instance variable? Wouldn't it be the same if first and second file just call new, which would return the same instance and then move Object.freeze into the constructor? Thinking it would be a cleaner solution
@WaldoTheWombat4 ай бұрын
Yeah I also didn't get that, Kyle already solved it in the constructor, so why can't the other files just the keep using the instantiating with the class?
@rahimco-su3sc Жыл бұрын
thanks a lot for your efforts , i really appreciate that
@skittlznt2611 Жыл бұрын
Very well explained. Thank you 🙏🏾
@ayabochman54532 жыл бұрын
Such a good example!! Thank you!
@Colstonewall5 жыл бұрын
I knew there was something I liked about You! Love the shirt. Any Zeppelin fan is a friend of mine. I'll shutup and sub, now.
@WebDevSimplified5 жыл бұрын
Thanks! Zeppelin is an incredible band and always enjoyable to listen to.
@ButtKraken013 жыл бұрын
Thanks for such a great explanation!
@samislam27463 жыл бұрын
*If somebody knows please help*, What will happen when you write: class X { constructor(){ X.instance = 8; // Here } } 1- What does X.instance mean? It's mentioned in the video nearly at 6:00 2- Where the X.instance is going to be? 3- What is the difference approach and using a static property?
@tyafizi3 жыл бұрын
1. It's mean that you set static property called 'instance' for your class X. 2. In the class like any other static fields. 3. Difference is that if you use this approach method you can't define an instance property without creating an instance of this class. class MyClass { constructor() { if (!MyClass.instance) { MyClass.instance = this; } return MyClass.instance; } field = 42; } console.log(MyClass.instance); //undefined const myClass = new MyClass(); console.log(MyClass.instance); //MyClass {field:42} (Or in your case 8) So all next instances will be known that you've already created some instance and instead of returning new X they will return that instance const newClass = new MyClass(); console.log(myClass === newClass); //true
@aryarifqipratama Жыл бұрын
Singleton adalah 1 instance object sifatnya shared reaource sehingga bisa di pakai oleh object lain
@vinayyadav-qr7rb4 жыл бұрын
thank'u
@passby8070 Жыл бұрын
Love this explanation
@yahelabraham9821 Жыл бұрын
great explanation, thank you
@Crazould4 жыл бұрын
your videos are awesome! thank you so much!!
@karthikkumaresan10914 жыл бұрын
awesome videos!! Keep them coming
@Mobin925 жыл бұрын
Singleton pattern is basically a glorified global variable. Change my mind. :^)
@WebDevSimplified5 жыл бұрын
You are completely right. I generally avoid this pattern, but there are cases where it can be useful.
@WaldoTheWombat4 ай бұрын
But fi you already modified the constructor to always return the first instance that was ever created, then why can't you just keep exporting the class instead of that object like you did in the first place?
@Carl-yu6uw4 жыл бұрын
Nice explanation, and use case, cheers. Do such singleton running on client side js commonly then persist their log array to db to allow after the fact debugging from one central place?
@tlev6153 жыл бұрын
Great explanation, and thanks for the video, just have 1 question, is it really necessary to do this manipulations inside constructor, if we import instance of logger it will be same instance for any file because of modules that are singletones anyway? Just wondering why we really need that checks here?
@someone7612 жыл бұрын
Same question!
@wiczus61022 жыл бұрын
If you work in a team, you want other people to use it correctly. Let's say it's the company directive to get the log count. If a person would by accident instantiate FancyLogger, they'd make a silent error. People will get the wrong log count and won't know that. If you make a class, you should make sure that others will use it correctly.
@johnnyxp645 жыл бұрын
my favorite pattern! :)
@WebDevSimplified5 жыл бұрын
Nice. What makes it your favorite. For my the command pattern is one of my favorite.
@johnnyxp645 жыл бұрын
@@WebDevSimplified is just that since i started coding with gwbasic back in the 90s there was no patterns like today and without any special reading when i was 10 and discovered i could share data info among different "screens" by using a common "module"(even in today's vb.net is still been used) that was so excited for me as a kid. so is my favorite just for nostalgia reasons 🤣🤣🤣
@WebDevSimplified5 жыл бұрын
@@johnnyxp64 That makes a lot of sense. Nostalgia is pretty powerful. For me the command pattern just really opened up how powerful clean code and design patterns can be which was really exciting.
@johnnyxp645 жыл бұрын
@@WebDevSimplified makes sense. is one of the pillars in OOP (command pattern) in my opinion and everything that uses encapsulation is helping the coder to focus on what matters and keeps indeed a clean and more readable code. 😎
@penggao26152 жыл бұрын
Hi Kyle, thanks for the video. I have a question regarding to this singleton pattern: what's the difference between using an instance 'logger' and using a 'static' class attribute in the class 'FancyLogger' to record the logs ?
@areebtariq6755 Жыл бұрын
Don't Know about JS but as for Java a class cannot be static , only its members can be static. A static member can be access by all instances of that class.
@areebtariq6755 Жыл бұрын
Here is a sample code for Java Singleton Class , which may clear the difference between Singleton and Static Member
@areebtariq6755 Жыл бұрын
public class Singleton { private static Singleton instance; private int value; private Singleton(int value) { this.value = value; } public static Singleton getInstance(int value) { if (instance == null) { instance = new Singleton(value); } return instance; } public int getValue() { return value; } }
@mohitbhatia1994h5 жыл бұрын
The best explanation !
@WebDevSimplified5 жыл бұрын
Thanks!
@vuejs12 жыл бұрын
Can we use this instead of FancyLogger inside the constructor of FancyLogger?
@jenstornell3 жыл бұрын
Is it a good idea to use singleton to simplify plugin methods, something like field.setValue(34); Then it's like a namespaced function where the plugin maker does not need to add new instances of the class.
@aryankumar87771 Жыл бұрын
is there a video on Factory Design Pattern ?
@nalditrinmartinho1781 Жыл бұрын
Can we say that some parts of state managers like Redux use the Singleton Pattern? Just to make sure I understood the concept here...
@marcosantonioreyesmedina23644 жыл бұрын
Hi, very good video. We have always seen the "Singleton" pattern applied to a DB Connection class, what do you think ... do you think it is correct to apply it in this case?
@nonnodacciaio7042 жыл бұрын
Yeah, that way you only have one connection and it's easier to manage
@mycommentmyopinion11 ай бұрын
Depends on the use case / how often you make calls to your db. Look into database connection pooling
@mahdiwebdevelopment23384 жыл бұрын
What is strategy pattern? Make a video on this. Thanks
@WaldoTheWombat2 ай бұрын
Hi Kyle!
@shivaganga91484 жыл бұрын
Could you do a video on repository pattern
@aneesahmad1682 жыл бұрын
O hooo 1K to Million sub 😻
@AcousticBruce3 жыл бұрын
I paused video and tried something first and then I finished your video and saw it was much different.. Does anyone know the pros and cons of my version? let L; class Logger { ... } if (!L) { L = new Logger(); } module.exports = L; Is there something wrong with this version? I did this in Node and because Node caches all uses of require, I figured this was okay.
@briefcasemanx2 жыл бұрын
Isn't a database just a singleton? Its a shared resource that can be used by many other processes for different purposes, instead of each of those processes having their own separate set of data. Am I wrong, or do people that don't like singletons not like databases either?
@audiodrocher4 жыл бұрын
Ohshhhh, this is llifechanging. Thanks a lot.
@louaykhammar72682 жыл бұрын
thanks
@anngular22272 жыл бұрын
Error: "To load an ES module, set "type": "module" in the package.json or use the .mjs extension."
Just wow! these days i was just looking for how to share class modules with other user objects. Just wow!
@mangotree96295 жыл бұрын
Nice explain by u
@WebDevSimplified5 жыл бұрын
Thanks!
@hugofilipeseleiro4 жыл бұрын
Thank y
@zum43423 жыл бұрын
holy shit 0 dislikes. imma dislike it ahahhaahah jk bro ur awesome
@JonesDTaylor5 жыл бұрын
great job.
@WebDevSimplified5 жыл бұрын
Thanks!
@peterzeng1243 Жыл бұрын
You are so handsome and smart. Clear explanation, thanks!
@___dh__dh__2 ай бұрын
Why no ;
@StuntmanJo2 жыл бұрын
Dope!
@samms79223 жыл бұрын
Now I know how mongoose works behind the scenes.
@juanyang8385 жыл бұрын
Are there any differences between singleton pattern and database?
@WebDevSimplified5 жыл бұрын
The singleton design pattern and databases are two completely different things. A database is a place to store information in an efficient long term place while the singleton design pattern is just a way to structure code so that you only ever have one global version of an object.
@juanyang8384 жыл бұрын
@@WebDevSimplified Then using a database to store an objects is waste and misused? I'm having a plan to create a small database for re-merging every properties on the same column and sending them back to the each instances just like how singleton does.
@WebDevSimplified4 жыл бұрын
@@juanyang838 I am not sure what you mean. A database is for permanent storage of things you need to access later. I do not really know what you are trying to do.
@pipertripp4 жыл бұрын
Zeppelin, nice.
@TheBatags5 жыл бұрын
Cool Shirt!
@WebDevSimplified5 жыл бұрын
Thanks! Led Zepplin is such a great band.
@augischadiegils.51093 жыл бұрын
❤
@aissa.bouguern3 жыл бұрын
We can also create a singleton via a factory function instead of doing it inside class constructor. That's much cleaner imo.
@awekeningbro120721 күн бұрын
This is not correct. Returning a value from a constructor is ignored and can lead to unexpected behavior.
@ahmedboutaraa87713 жыл бұрын
.....
@yiminzhou79353 жыл бұрын
you are so handsome
@knackofabhinav2 жыл бұрын
so redux is singleton 🥲
@seanzoso4 жыл бұрын
Led Zeppelin
@greydiamondplayz20785 жыл бұрын
Singleton is my last name
@ZikoMario3 жыл бұрын
You have got 0.1% dislikes on your video, that is insane.
@Rebel101 Жыл бұрын
Incident implementation. It should just be a module, not a class.