Daniel Marcotte on SproutCore 2.0 (now Ember.js)

Daniel Marcotte is one of the top developers on our latest product offering, Customer Intelligence (CI). He spent quite a bit of time evaluating SproutCore 2.0 for the complex user interface requirements of CI, helping to work out some of the kinks in the product as it moved toward beta.

Daniel has recently moved to San Francisco to work on a new project — still for Bazaarvoice, of course! Before he left, I had a chance to sit down with him to chat about his experience working with the framework.

MDN: Welcome, Daniel! Thanks for letting me take some time out of your hectic schedule to get you on record, so to speak.

DM: Ah, my pleasure, Michael. Thank you for doing all the hard work.

MDN: No, no, not at all. You did all the hard work already — I’m just gonna put my name on it!

DM: I’m a team player; you go right ahead!

MDN: Awesome! So let’s get right down to it. You switch seamlessly between front-end and back-end development, and you’re very passionate about the user experience. A lot of developers in the industry want to work on back-end systems and don’t seem to get as excited about building great UIs. So, what do you think contributes to your passion? I’m really interested to hear what drives you because it also tends to drive the Web UI frameworks people choose.

DM: Yeah, that’s fair. I’ve actually given this a little bit of thought because my new manager asked me something about this recently. Something like, ‘Wow, you know, you’re really a UI guy. That’s great; how did you get into that?’ And I had kind of a funny moment, thinking it might be fruitful to start thinking of myself as a UI guy because then it’ll focus me on taking time to even go the extra level. Maybe read some stuff about user experience and even more wacky technologies. Because, I hadn’t traditionally done that. So how did I even end up in this position where someone would think, ‘of course you’re a UI guy’?

I think it’s because I don’t wanna do a shitty job. So if you’ve been tasked with building a UI feature, it needs to work. And it needs to be attractive. It needs to be usable. You need to put yourself in the user’s shoes.

MDN: It’s amazing, but most people don’t think that way. It seems like you actually know a little bit more. Have you actually done any reading and learning about any of this?

DM: I have, yeah…some. But nothing extensive. It’s a bit intuitive which I think gets people relatively far. And I think it has a lot to do with just being honest with yourself, of trying to put yourself in someone’s shoes maybe.

I have a bit of a teaching background. It’s one of my great pleasures. (Let’s ramble a little bit.) And one of my favorite things was being able to find a way to explain something to someone who it was completely new and novel to. To never forget what that was like to learn it for the first time. ‘Cause you can get lost and be an expert and think, ‘oh, it’s obvious, it’s fine.’ And I think that bleeds into UI sometimes. ‘Oh, I know how to use this.’ And that’s not the bar we’re trying to meet here.

MDN: You were instrumental in choosing SproutCore 2.0 for CI. What other Web UI frameworks did you and the team look at before deciding on Sproutcore?

DM: I looked at what Dojo was offering because it has the same full app/infrastructure stuff. It was a touch inscrutable, but really appealing. But it kind of seemed to go down the Ext-JS packaged-widget route. And I knew that Alex Zelenak, our UX designer, would come in and do a lot of custom stuff. And the other big driver, though I’m perceived as choosing this, I was really just the person who made it possible. It was really Alex Sexton that said, ‘this is the one; this is it for these reasons.’ So that kind of focused it. And it sort of became the one, and it needed to lose for some reason as opposed to beat something else.

MDN: Did Alex talk about Handlebars at all, because I know that he’s using it in other places.

DM: Oh, that’s interconnected. You use Handlebars templating inside SproutCore.

MDN: I’m just showing my ignorance!

DM: It’s like a specialized version of Handlebars that’s bindings-aware. So as your values change, your templates re-render.

MDN: You talked about this a little bit, but does SproutCore have widgets too?

DM: No. They’d like to get there, but it’d be like a UI layer. This is more like the structure/spine of the app.

MDN: So other than Alex’s stamp of approval, what are the other reasons you might use it in the future?

DM: I like the way it makes me think. I like the flavor of thinking it lends itself to. This disconnect with the bindings…. (Let me see if I can package this a little bit.) Trying to wrangle web UI using HTML, CSS, JavaScript without making the classic disaster, the classic mess, has been a mission of mine for a while. What’s the answer? What’s the secret? How do we make this maintainable and obvious to the next developer? Extensible, that sort of stuff.

And one of the big realizations I had a while ago was, with Don’t Repeat Yourself, the DOM, it’s the boss in so many things. I have a list of things I’m showing the user, and I don’t wanna duplicate in JavaScript having another list of things and try to synchronize those two. It’s much more a matter of saying something like… DOM: you’re the boss. You’re displaying it. You have these nodes that represent my things. So if I need to reevaluate, I’m just gonna ask you, ‘Hey dude, what’s my list look like?’ OK, I’m gonna modify it inside you ’cause I wanna display it. ‘Cause you’re the boss. And so in practice this works out really well.

MDN: ‘Cause that’s kind of how JQuery works because you have this separate set of code over here and it’s overlayed on top of the DOM.

DM: Yeah exactly. But for some richer apps and much more complex apps, asking the DOM those questions gets more complicated ’cause stuff is kinda all over the place. And so you end up with these really bonkers selectors. And it’s slow to be constantly asking the DOM these questions to see what’s going on with it. So then you start to pull back and say, ‘Oh, crap, I wish I had an object representation of this in my hand!’ Is it worth writing this connective tissue? And so now, enter SproutCore, and the app is sort of pure JS and then you bind it to the UI and you don’t maintain that connection; SproutCore does. Which is cool.

So the classic collections example that ties into the list example earlier, where before the DOM was the boss, now javaScript’s the boss. I have this list and I’m gonna monkey with it. Using observers and bindings, SproutCore’s gonna hold onto the fact that the list corresponds to something in the DOM, that’s rendered by a template. When the data changes, the template is called to re-render that piece.

MDN: So SproutCore owns the DOM then.

DM: Effectively, and it can do smart stuff like buffer your updates. So it’ll just be like manually updating the DOM, but will be a lot faster. Then you kinda get into their flavor of MVC. SproutCore MVC gets quite appealing where you can really build an app that does its thing and then you can write unit tests against that. And when you bind the UI on it, that’s just another view. But independently, you have this app that you can validate does its thing and is independent of how it’s displayed. You do have to make sure you structure it carefully enough that you’re not getting into circular references in your bindings, but it’s super-appealing that your templates are HTML and you just bind them in with the app and there’s a lot of really great ideas. It’s technically very satisfying.

MDN: And do you just bind it on top of a div element, because you’re going to have to put it in somewhere, right? So there’s some ID where you say, hey put this over here in this spot?

DM: You have a script block that has a type “text/html” or “text/x-handlebars”. And one of the first things SproutCore does is it looks at the page and any script block of that type, if it has an ID on it, then it assumes you’re gonna reference this later and so it will just pull it out of the DOM and store it compiled. Otherwise, it’ll replace it inline. You get to write very naturally, right inline, if you’re not reusing that component. It’s got a nice flow to it where it will just replace that piece with the markup it corresponds to.

MDN: Did you run into any problems with SproutCore’s architecture as you were building out the system at all?

DM: So, to even decide if we wanted to do this, I threw together a prototype that recreated what the pilot’s UI — the interested parts — did. And I was really able to see the value because we’re managing different views on the same data. And the user gets to toggle displayed data and interact with what they’re seeing. And so this idea of an app that will hold that state and where you can just swap out these views, it’s great because you can just say “app, here’s some data, do your thing” and now you’re not fetching from the server again and again if you just wanna re-slice something or have a different look at it, you have all that power easily in the client side.

So that was all going really well, but then I’d run into mundane stuff. Like: you’ve sent in a collection and you’re running over it and the designer wants to number each row. Perfectly reasonable request, but the context that you have in the collection rendering is just the collection item that you’re on. So do you artificially start adding indexes to your objects externally? Or do you say we should really have access to the index? And so that was kinda fun; I submitted a patch which exposed the current index when rendering a collection. Another example is that Tapestry [the server side web framework in this project] hosed us because you have almost no access to the head of the documents that it generates, which in general isn’t a problem, but in one of the early versions of SproutCore, it was only looking for stored templates in the head, which was an artificial restriction.

MDN: But not really any big pains or roadblocks. Nothing you couldn’t work around or fix.

DM: There was naturally a bit of instability in a few of the alpha versions I was using. And then there’s a tougher learning curve that goes with that: you can imagine being unable to distinguish between a flaw in understanding and a flaw in the library. But that’s come a long way.

There are also things that it really super-facilitates incredibly, but as with a lot of these things, it can mean limiting you in other ways, like there being hoops to jump through to integrate with say a select control.

And then we got into trouble where other developers started building out what I had there, and it wasn’t obvious that this code worked differently than they were used to. I hadn’t quite gotten it polished to the point of “this is how it’s done and you grow it from here and follow these patterns.” I hadn’t quite gotten there. The schedule comes in and you end up with this problem. So there was a bit of: “I wanna do this thing, and I can picture that vision in the ‘JQuery way.’ Well now, what’s the ‘SproutCore way’ of doing exactly that?” And you end up kind of cheating and creating artificial properties that you can bind to and kind of tricking it into doing things the ‘JQuery way’ instead of doing what is really the ‘SproutCore way’. And that’s really challenging.

MDN: Well, it’s the speed of sort of doing it versus doing it in a way that it’s gonna be good later.

DM: Yeah. Do you want the speed now, or more of it later? And that’s a really hard choice to make. And I’ve been ruminating on whether that’s a flaw on our part, or on the library’s part. How do we keep pushing that stuff forward and make it even better? I’m not sure.

MDN: You made a pretty concerted effort to get SproutCore out of beta and into mainstream for release 2.0. So, you actually fixed a couple of issues. How did that process go? How did you work with the team and get them to take your patches?

DM: Contributing to open source had been mysterious to me for a long time. And I’ve met a lot of people who are also like, ‘oh I want to contribute to open source, but I kinda like don’t know how. And IRC makes me cross-eyed.’ What do you do? In a lot of ways, this was just sort of really kinda lucky — a nice sort of confluence of events. And in my mind some of the things that made it possible was actually meeting Tom Dale and Yehuda Katz (who are great, by the way) and shaking their hands [at TXJS]. And they don’t have to remember it, but that’s kinda your way in later to politely say, ‘Hey, remember when I expressed interest in your framework? I’m using it and I don’t need anything from you. I’m just sharing good news. I’m not after you for anything.’

And then, GitHub makes a lot of this brilliantly easier. You make your fork, you monkey around, you learn something. Figuring out how Github works is pretty straightforward. You still see some trolling and joke pulls and this sort of stuff, but it’s kind of neat and friendly once you get your head around it. So then to contribute to a project: Keep it small. Keep it focused. Explain why. Write a unit test for whatever you’re putting up. And then you just post it, and then you wait.

I also started a bit of not-constant (it was a real priority for me not to bother these guys) but still regular e-mail correspondence with Tom Dale, so I think for my initial patches, the SproutCore guys were able to connect them with me. So I think it sort of gets you in the door that you’re not just some random unknown pull request. And then it was pretty easy. It was super satisfying to get even simple messages like, ‘Hey, thanks!’ And then they merge in your code. and that’s pretty cool.

Being able to take some time to work on that at BV is brilliant. People knew that I was investigating some of this stuff and there was a lot of support. It was cool. And John [Daniel’s manager] got a lot of satisfaction seeing my patches going in and that sort of stuff. So yeah, it was really cool.

I still think navigating all this is kind of hard. It’s social. You get self-conscious someone’s probably going to be a dick to you. Someone’s probably going to ignore you ’cause you’re nobody. But this experience was really good so it’s worth trying more. And I would encourage other people too: find something you’re passionate about, some little tool you use you wish worked a bit different. You’re probably bright enough at this point; you can actually figure out how to make a useful change, even just for yourself initially.

MDN: What kind of support did you get from the rest of the R&D organization here? You mentioned you could do some of it during work hours, which is great.

DM: I just tried to not be stupid about it. As long as I was being productive and watching my diminishing returns level, I was free to put in the time I needed. The VP of Engineering said we should at least try and do something interesting. He wanted to know “Is that feasible?” And so that’s the kind of support. I’m like yeah, sure, I believe that it’s feasible and I have a vision for walling it off so we’re not betting the whole product on it. I can try, but you’ve just introduced some risk that we may have to pay for, we may have to mitigate. And he was fully supportive, and so when that directive to try something fresh comes from that high up, that’s kind of the definition of support. You know what I mean? And I felt like I had the freedom to at any time make the call that we were going to bail on that course of action (the diminishing returns thing). I don’t think anyone would have turned on me and been like, ‘what the hell, Daniel, you didn’t even use that technology. You spent all that time on it.’ I think they would have been like, ‘Thank you for actually evaluating this and making a technical decision.’

MDN: So, would you recommend SproutCore 2.0 for everybody?

DM: I have no idea. It was still in its infancy during this project, so “everybody” seems a bit strong. But I really enjoyed using it, and I’m looking forward to using it more and watching it grow.

MDN: Thanks Daniel, for taking the time to chat with me! It was very educational.


Daniel brought in his laptop and showed me https://github.com/dmarcotte/ember-chess. Specifically, we walked through his very informative presentation in just a few minutes: https://github.com/dmarcotte/ember-chess/blob/master/presentation.js.


Thank you for sharing this interview. I’m evaluating ember now, and it really excites me that we are finally seeing an appeal to structure and proper separation of concerns on the client-side in JavaScript.

I too am a “hybrid” developer of sorts, with the user experience being at the forefront of my passion and enjoyment. It’s a good place to be nowadays; I remember not too long ago when the art of UI was not getting the respect it deserves. I think Steve Jobs did a good job of helping correct that.

Anyway, having a fellow UX afficianado come off a successful project with ember is pretty encouraging. I’m now pretty confident I’m heading down the right path.

P.S. ctrl + h, sproutcore, tab, ember, enter 😉