Classy: Cleaner class-based controllers for AngularJS | Hacker News Reader

Classy: Cleaner class-based controllers for AngularJS

davej.github.io

139 pointsLX-35057 comments

There is really no need for this. It adds nothing imo but another layer of sauce over what angular already does properly.

If your controllers are getting huge, go refactor into directives and services. I don't see how this would help since there isn't even inheritance?

also:

    app.controller('AppCtrl', ['$scope', '$location', '$http'], function($scope, $location, $http) {
    // ... 
    }]);

    app.classy.controller({ name: 'AppCtrl', inject: ['$scope', '$location', '$http'],
      //...
    });

Congratulations, you have saved absolutely nothing (10 bytes? ) and just made it harder for me to understand your angular app.

One of the brilliant things about angular is that it provides a proper structure that anyone that needs to write angular needs to adhere to. If you start introducing layers upon layers of funkyness and glitter, you'll end up with something non-angular.

what I mean by that is: Classy introduces new conventions in a frameworks that already has a lot of conventions to keep track of while coding, and my biggest argument against this is that you introduce a dependency to Classy for all code based upon it, therefore you've created an extra layer of complexity to fix and track down when angular changes.

In my mind effort like this should go into the angular core to make it better.

Thanks for the feedback. I would argue that the Classy example is more expressive and crucially it is DRY.

Edit:

> One of the brilliant things about angular is that it provides a proper structure that anyone that needs to write angular needs to adhere to

Angular doesn't provide structure for controllers, they are just javascript functions. If you want to add structure it is up to the individual developer to decide how to do it. Classy is just the way that I like to do it, Classy is opinionated so it won't be for everyone.

By the way, you can do inheritance but I haven't documented and fully tested it yet.

Angular's dependency injection is still a matter of discussion and a lot of people are not completely happen with it. It'll also be made into something different for angular 2.0.

Still, besides that: DRY is IMO not about these 2 lines that you've refactored away here. It's about whole functions/classes that have similar functionality where you're repeating yourself.

Therefore, this would be a micro-optimisation with negative results on impact on performance most likely (since there's more overhead)

The point of DRY is to reduce the types of errors that repetition lends itself to. A very common member of that class of errors is "I should have repeated something, but I didn't". It is pretty easy to run into that error with Angular's injection - you can forget to add either the string or the argument, or (worse) you can get the order wrong. Eliminating the repetition fixes that class of errors, so I think it's well within the realm of "what DRY is about".

I can see Classy adding value, but repetition with dependency injection is a solved problem if you use ngmin[1].

[1]: https://github.com/btford/ngmin

I disagree that ngmin is a full solution to the problem. It is a good and very helpful tool, but it's a hack and a pretty leaky one - I think it's often less of a hassle to just write all the explicit injection syntax myself than to fiddle with formatting to get ngmin to work and track down issues when it doesn't. Classy's solution seems much nicer to me.

I have no idea what you're talking about; I've never had any issues with ngmin or angular's default (i.e. non-array / string) injection methods.

I guess your mileage may vary, but in my experience, it isn't difficult to write reasonable code that ngmin fails to handle properly, and it's difficult to debug when it happens. It seems the best thing to do is to start with ngmin from the get-go and adopt a style guide that works with it. But I like the idea of a library that abstracts it away altogether.

I ran into this exact thing just a few days ago. I added a dependency to an existing controller, and it threw an error because I'd only added the dependency in one place instead of both.

This is absolutely one of the things that DRY is about.

> Angular doesn't provide structure for controllers, they are just javascript functions. If you want to add structure it is up to the individual developer to decide how to do it.

This is a pretty big one to me. Angular provides tons of structure all over the place, with only one real exception: controllers. Some of my controllers stick out like sore thumbs in my code. I like how Classy gives them some structure not unlike the structure that directives already have.

I would argue that if your controllers are getting that complicated, then you're doing it wrong.

Wouldn't you need to be doing `var self = this` in every function you have nested anonymous callbacks touching $scope though?

Yes or function.bind() or fat-arrow in Coffeescript. It's usually best practice to move that kind of stuff into a service instead though.

Look a little closer - It's not about saving bytes. I ended up coming up something very similar for my projects and it made a notable difference in defect rate.

- Removes the need for positional arguments for constructor injection, so you only have to list your dependencies once. This one seems minor but can be a major frustration and a source of bugs when working with lots of services.

- Moves actions out of the scope and onto the controller itself, where they belong.

- Provides a clean template structure for other project members to work off that guides you to nicely structured and properly separated code (i.e. Watches in one section). This seems minor, but when you're working with multiple junior developers it starts to become a big deal very quickly.

You can do all this without using a third party project, but if you're new to Angular this is a nice bootstrap and helps guide you towards a solution that avoids a lot of warts in the framework.

"- Moves actions out of the scope and onto the controller itself, where they belong"

Based on the Classy's docs, it doesnt "move" actions out of the scope and onto the controller, but the other way around. It adds controller's actions to the scope unless you prefix the names with an underscore.

Based on my experience debugging angular performance issues associated with expensive $digest cycles, I do NOT WANT it to happen automagically. I only want those functions on the scope that i explicitly place there.

But angular only watches functions you tell it too. What's the harm in attaching a function to the $scope if it isn't used by an angular expression?

To be fair ngmin already fixes the injector problem, in most cases.

It's the "in most cases" that'll get ya!

The feature of angular-classy that looks appealing to me is reducing the constant repetition of $scope. You still need to use this.$ or this.$scope when manipulating scope variables, but at least it hides it in the case of definition of scope methods.

This is actually great for someone learning Angular. It's just a different way of presenting the exact same material. I was completely dumbfounded at first when learning Angular. This would have helped.

I very much suggest everyone interested in Angular development to read what the guys at MeanJS.org[1] have to say about structuring modules. It helps me think about my app a lot better. The structure could be cleaned up a bit though (e.g. module A can use module B's filters at run-time, this is a bad thing IMO. There should be global and local filters).

[1]:http://meanjs.org/docs.html#angularjs-modules

I just want to let you know that I really appreciate your empathetic suggestions for those [like me] trying to learn intermediary aspects of AngularJS; of which I am going to relate to—the learning of how to walk——and then applying that knowledge to break atmo and venture into the stars. :)

TLDR; THANK YOU (Intermediary AngularJS learning–curve is friggin hard.)

You're welcome. I am an AngularJS neophyte as well... but the mental picture I have of the framework is definitely clearer than it was two months ago!

Very nice! I am doing a project with angularjs right now to learn and it's really interesting. If you have other resources that explain how to do things the right way it would be welcome.

I would go with writing directives over using global scope in general, though it's more time consuming to me.

But I need some filters to be "global" and some to be "local". I need to call some in different modules, while some are useful only in one particular module.

I haven't found out how to do this yet. Not fixing it until it breaks, even if that means I'll have to re-write parts of the app.

Oh wow, this is my little project, cool to see it on the front page of Hacker News. :-)

I think there is a small typo in the example on the page, there is a missing comma after the closing "watch"-bracket.

It's a really nice demo page. What do you use for the code highlighting?

Thank you. It's just CSS and the :hover pseudo-selector, the popover effect is done using CSS keyframe animations.

Fun geek fact: The Mac OS style close/minimize/expand buttons on the code editor are written in CSS, they're not images. A bit of a pointless exercise but a fun little easter egg.

My initial run-through of it leaves me thinking it's absolutely brilliant, which isn't generally a word I use lightly.

So long as non-Classy controllers are still operable (which I assume they are), then I should be able to port individual controllers one at a time without disturbing un-ported controllers, then this is exactly what Angular was needing, IMO.

Interesting project--I've done a little bit of Angular development and would be curious to look at this the next time I come back to Angular.

As a side note, I am always impressed and insanely jealous of the nice websites that frontend libraries make for themselves. It makes sense since obviously folks with more frontend experience are writing the libraries, but I wish there were nice templates or tools to make such nice and informative pages. Would be cool to see stuff like python, boost, etc. with clean, responsive, easy to read web pages.

In relation to your side note, perhaps a site like http://html5up.net/ might be of use. I'd be interested if others have other similar resources they use.

Wow, those are super slick. Thanks for sharing.

Github can generate project pages for you with a few different layouts. Nothing fancy but a decent enough design with almost no effort: https://help.github.com/articles/creating-pages-with-the-aut...

I've experienced the problem of unwieldy controllers myself, but angular is already such an intricate, opinionated framework that I can't imagine adding another layer with its own DSL. Good code organization solves a lot of these problems.

I've noticed that particularly in web development there is this trend of writing - and using - countless frameworks that add much more complexity with little gain, and where the response to existing complexity is to... add more of it. IMHO that doesn't seem like a very good way of doing things, since now you have to learn not only JS, but also all these extra indirections piled on top, to understand how your web application works. It's not doing any favours for the browser that has to run all this code either. On the whole, this just feels to me like an immensely wasteful way of doing things.

Definitely true in general though angular in particular is SO GREAT that it is worth it. But it certainly doesn't need MORE layers like the one in this post.

I was about tu post the same comment. I can't imagine maintaining a code using angular and another layer on top that adds another syntax on top of scopes, bindings, and controllers. Sorry to whoever did that lib for the critic. That was obviously a big task and it really is full of good intention.

No need to apologise. I created the library for myself first and foremost, it's opinionated and it won't suit everybody but I'm ok with that. :)

Looks interesting, I might try it out on my next Angular project (starred it to remember for the future).

As a side-note (don't mean to hijack this thread) but I always wondered why a service doesn't exist that sits on top of GitHub that allows for reviews/commentary beyond just issues on all these cool GitHub projects. There are so many awesome projects that look really interesting and I want to integrate into a project I'm working on but have no way of really knowing how effective or relevant they are without actually trying it (which sometimes works out but sometimes ends up being a waste of time). Just a thought, wonder if anyone else here at HN sympathizes.

I do (sympathize, that is.)

I see people using issues for this sort of meta-discussion on newer projects. Sometimes that feels wrong and sometimes it doesn't.

+1 for being interested in something more purpose-driven, if it could get adoption.

Search Twitter, /r/programming, HN, Stackoverflow, or Google for the Github project and read opinions. Works 95% of the time. (Also bookmark this thread and come back to it in a few days)

That's definitely my flow right now -- unfortunately that works best for bigger projects but less likely to find material on smaller projects you know?

I like this. One thing I like about is it how it sets up a canonical place to init things.

The other nice effect is the use of the injector instead of the repeated list of dependencies.

When not using coffeescript in angular, I could see making good use of this. Thanks !

It works really well with Coffeescript too. In fact it was written with Coffeescript and internally it uses Coffeescript's `Class` syntax.

It was originally inspired by this gist: https://gist.github.com/elado/8138516

I could see one annoyance being the lack of "fat arrow" in normal javascript and trying to reference the services in a callback.

There's a lot of conversation about the redundant injector syntax in this thread. This is something that ngmin takes care of completely transparently. There's really no need to worry about it in raw, uncompressed source code. Other than that, this provides a nice way to enforce a certain set of conventions, but I'm not completely sold on the quality of those conventions - the most glaring thing being losing references to your watches. Reverse-binding controllers to views through DOM selectors also has a bad code smell IMO, feels a bit like reverting to jQuery madness. I prefer to do this through routing or directives wherever possible.

ngmin isn't really a solution, it's a post processing transpiler hack. There's lot of ways to format your js code so that ngmin does the wrong thing and destroys working code. I wouldn't call the problem 'solved'. At least not until angular 2.0 or a solution like this.

A more clever approach would be to be able to register controllers as services through a classy service.I dont like the fact that you extend angular iteself with a new method on the module object.

And then angular internals get updated and it breaks...

This seems interesting. Definitely going to give it another look when I have time to clean some things up in my app. The controller DEFINITELY do get unwieldy after a while.

I guess this can clean logic flow in a controller, but here you end up with a bloated object instead.

The biggest problem I see though is if you want to save a reference to the unregister functions of the $watch callbacks.

Otherwise, this is a cool idea, although it falls a little short.

> The biggest problem I see though is if you want to save a reference to the unregister functions of the $watch callbacks.

This is a valid criticism, thank you. I will try to put together a nice solution for this.

Of course you can always register/de-register watchers the normal way inside of the init method.

Yup, I'm aware - nice work on this so far!

Typescript classes work nicely with Angular controller I find. Coffeescript ones too.

Afaik you cant declare anonymous classes in typescript,let alone wrapping them in a closure.

No problem with Coffeescript.

    module.controller 'MainCtrl', class
        constructor:($scope,bar,baz)->
          $scope.message="foo"
        @$inject = ['$scope','bar','baz']

that's why i prefer the later.types or not.

I don't use anonymous classes for controllers so that's not an issue for me but if you want to use them, I don't think there's a way to do it in typescript

The fact that you can flip the entire page into Coffeescript mode is BRILLIANT. Also, love the tooltips that come out of the code blocks.

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