Learning from Twitter

http://ejohn.org/blog/learning-from-twitter/

by flapjack • 16 years ago

209 36 16 years ago

eapen• 16 years ago

Why isn't John a billionaire already?

jeresig4• 16 years ago

Heh, while I assume that this was mostly rhetorical and largely tongue-in-cheek it is a question that I've been pondering lately. (Or, more accurately, thinking about what work excites me.)

I've been working on jQuery full-time now for about 1.5 years (sponsored by my employer, Mozilla). Prior to that I worked on jQuery in my spare time for about 4 years while doing other things (I was in college, then in Y Combinator - Summer 2006, and then worked for Mozilla as a JavaScript Evangelist).

I've managed to pigeon-hole myself into the position of a JavaScript framework maintainer rather solidly (for better or worse).

That being said I really enjoy what I do and have trouble thinking of something that I would rather do as my day job. Being able to work on a piece of code that I've largely written from scratch and promote it to a community of eager users is my dream. I've often thought about making a leap into something else but struggle to think of something that would hold my interest as deeply.

I'm largely not interested in starting or joining a business. For whatever reason I frequently find that attaching a profit motive to work largely impedes my ability to be happy and seems to run contrary to my overall goals (educating people, giving good tools to developers -- and providing both to anyone and everyone, no restriction).

Perhaps I'll find some interesting project some day that will open the financial floodgates (or perhaps I'll enter a situation -- such as having children -- that will necessitate me earning more than I do now) but I'm quite content now where I am, doing what I'm doing.

All this being said, I'm constantly looking at and exploring new things. At the moment though most of that is outside the realm of JavaScript, or even computers, and mostly relating to art. It's unclear to me if that's something that'll hold my long-term interest (although it has for the past few years) but we shall see.

johns• 16 years ago

I didn't know you were part of a YC company. Which one was it?

theodore• 16 years ago

In my life, discovering jQuery is what made front-end development fun again. I think we're incredibly fortunate to have people like you helping us build software, and if it was possible to measure the aggregate impact of your work it would be staggering..

revorad2• 16 years ago

I'd love to hear more about what art you are involved in (besides jQuery of course!).

dionidium• 16 years ago

I use a generic version of the waiting-for-pause trick:

    // execute callback only after a pause in user input; the function returned
    // can be used to handle an event type that tightly repeats (such as typing
    // or scrolling events); it will execute the callback only if the given timout
    // period has passed since the last time the same event fired
    function createOnPause(callback, timeout, _this) {
        return function(e) {
            var _that = this;
            if (arguments.callee.timer)
                clearTimeout(arguments.callee.timer);
            arguments.callee.timer = setTimeout(function() { 
                callback.call(_this || _that, e);
            }, timeout);
        }
    }

Use it like this:

    document.addEventListener('scroll', createOnPause(function(e) {
        // do something interesting here
    }, 1500, this), false);

Edit: Oops! The version in the article runs some code if any scroll event occurred since it last fired, but this one doesn't execute the callback until the user stops scrolling for some amount of time. Anyway, maybe it's still useful for some folks.

mcav• 16 years ago

I've used that idiom too. It's a great trick. One potential issue is that if you continuously trigger the scroll/resize event, your callback will go an extended time without firing. That's usually only a problem if you're using it to adjust UI elements on scroll/resize, in which case you'd want to add a timer to force the callback if the delay has been too long despite the event still firing often.

long• 16 years ago

For anyone that's interested, two related techniques are called "throttling" and "debouncing".

ryankirkman• 16 years ago

Both of which are available in the awesome Underscore.js library: http://documentcloud.github.com/underscore/

bretthopper2• 16 years ago

It's good to know that this situation will lead to improvements in jQuery.

However, I'm disappointed in how twitter, or more accurately, Dustin Diaz handled this situation. They identified some performance issues. Narrowed it down to a jQuery version but just left it there.

jQuery is open source so they could have done some investigating on their own and tried to narrow down what changed in that selector. Especially since this change was blogged about (as mentioned by John).

Not to mention various people helped out twitter by finding some pretty obvious flaws and made suggestions. Twitter has a lot of resources and I'm assuming a lot of talented Javascript engineers. This is a situation where they could have used their resources to contribute to an open source project instead of the other way around.

gfunk911• 16 years ago

I don't think it's fair yet to say that Twitter won't do these things. The first step was fixing the regression as fast as possible.

bretthopper2• 16 years ago

Well there's not much else to do. It seems other people did most of the work for them.

jfager• 16 years ago

And the second step was writing a highly-visible blog post slagging the free code they use in their many-million-dollar website before they actually understood the problem?

dmethvin• 16 years ago

I'm on the jQuery core team. As you might guess, when a high-profile site seems to be having troubles with jQuery, we want to fix it whether it involves a bug fix or tutorial help.

It would really help us out if people could slip our pre-release versions into their test environments. There's a 1.5 beta available now (http://blog.jquery.com/2011/01/14/jquery-1-5-beta-1-released...). Don't wait several months to try it the way Twitter waited on 1.4.4, or we may ship 1.5 with some bug that impacts your site.

didip• 16 years ago

Deployed on production already (http://cdn.mybucket.co/static/js/jquery-1.5b1.mini.js). I minify it using Crockford's jsmin script.

We happened to use http://www.infinite-scroll.com, which also bind to window scroll event as well. Let's see how it goes.

Thank you so much for all the hard work that goes into jQuery.

btipling• 16 years ago

>since scrolling itself didn't change the DOM

Scrolling did indirectly change the DOM as you load more tweets when you scroll. But the point here is that the actual scrolling is not changing the DOM, the append is, and that's probably when you should update your query cache.

brown9-2• 16 years ago

I interpreted this as meaning that not all scrolling changed the DOM, only scrolling that reached the bottom of the window.

blago• 16 years ago

jQuery makes things almost too easy. As a result it gives confidence and power to a lot of people to write code that despite all sillines will still work. A professional JS developer would've debounced the scroll events and cached the selector results.

catshirt• 16 years ago

jQuery, while used & loved by my team, has made hiring vastly more difficult.

axod3• 16 years ago

jQuery promotes bad practices. People assume $('something') is a cheap variable access, when in fact it could be pretty slowly executing several functions. So they don't bother caching anything.

po• 16 years ago

I think by "promote bad practices" you might mean "abstracts complexity away from the developer".

This is true of just about any API. Nobody blames the API when their ORM layer generates a massive SQL query based on complex query input. Understanding the performance characteristics of the 'backend' is assumed.

Charuru• 16 years ago

What in the world. I expected something interesting, but this is some major fail by twitter. Not caching selectors just boggles my mind. How can a million dollar web company do this?

cabalamat2• 16 years ago

This sort of thing is one reason I hate websites which use a lot of Javascript when they don't need to. Another reason is that it breaks expectations of how websites should work.

larrywright• 16 years ago

To be fair, the expectation of how websites work is changing. Lots of small touches in applications aren't strictly necessary(animation, transparency), but they do make for an overall nicer experience. People have come to expect these things from modern websites.

cabalamat2• 16 years ago

> Lots of small touches in applications aren't strictly necessary(animation, transparency), but they do make for an overall nicer experience.

I can't offhand think of a single example where they've improved my experience. (With the exception of things like Google Maps where the JS is an important part of the user interface.) When, for example, a menu or picture animates open instead of appearing instantly, at best I feel mild irritation.

Maybe I'm just a cumudgeon.

Learning from Twitter

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