Archive for December, 2011

Using jQuery’s .pushStack() for reusable DOM traversing methods

The .pushStack() method has been in jQuery since before version 1.0, but it hasn’t received a whole lot of attention outside of core developers and plugin authors. While its usefulness may not be immediately apparent, it can come in really handy in some situations, so I’d like to take a quick look at what it does, how it works, and how we can use it.

pushStack Basics

At its most basic level, the .pushStack() method accepts an array of DOM elements and “pushes” it onto a “stack” so that later calls to methods like .end() and .andSelf() behave correctly. (Side note: As of jQuery 1.4.2, you can pass in a jQuery object instead of an array, but that isn’t documented and jQuery itself always uses an array, so that’s what we’ll stick to here.)

Internally, jQuery uses .pushStack() to keep track of the previous jQuery collections as you chain traversing methods such as .parents() and .filter(). This lets us traverse through the DOM, do some stuff, “back up” to previous collections within the same chain using .end(), and then do something else. Here is a somewhat contrived example:

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