Sometimes, you might want to overwrite built-in global methods like setTimeout and setInterval. If you try, you might find that it's much harder than you think to accomplish this in every browser, particularly if you ever want to find the originals again. After a lot of painful experimentation, I think I have a definitive solution that works in all browsers with minimal side-effects.
I started ...
There's been a lot of discussion this week about the "hashbang", that ugly little bit you find in the middle of URLs like this one: http://twitter.com/#!/ded/status/18308450276. I wanted to provide a rebuttal to the arguments that the hashbang is bad for the Web, based on a lot of discussions we've been having inside Twitter since the #newtwitter project began last summer ...
Included in the laundry list of new features that are descending on the world of web development with HTML5 are two quite nice ones: History Management and the hashchange event. These two features allow for much richer and faster JavaScript applications. Let's start with a quick overview of what these provide.
This event is quite simple. Whenever the window.location.hash property changes, by following a ...
The engineering culture at Twitter requires tests. Lots of tests. I haven't had formal experience with JavaScript testing before Twitter, so I've been learning a lot as I go. In particular, a number of patterns I used to use, write about, and encourage have turned out to be bad for writing testable code. So I thought it would be worthwhile to share a few of the ...
When writing unit-tests for code, a common technique is spying, where you set expectations on a method's invocation, run some code, and verify that the method was invoked as expected. This is pretty straightforward. Here's a simple example using JsMockito:
function foo(a) { return a; }
foo = spy(foo);
foo(1);
verify(foo)(1); // verified!
verify(foo)(2); // never run
Here, we're spying on the foo ...
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