Question

I’ve recently come across a code sample I had to use, and I was able to use it, but I didn’t quite understand exactly what was going on.

Here’s part of the code:

.sortElements(function(a, b){
    return $.text([a]) > $.text([b]) ? 
        inverse ? -1 : 1 
        : inverse ? 1 : -1;
}

I know that this function is deciding which element should be sorted first out of a and b, and I know that inverse is deciding the sort order, but I don’t know what $.text([a]) is doing. Is it parsing a as text kind of like parseInt(a) and Date.parse(a)?

Google could not help me. I’ve also looked into the jQuery site and all I’ve found is

$(selector).text(), $(selector).text(newText) function.

Here’s the Fiddle I’m basing my code from http://jsfiddle.net/gFzCk/

Answer 1

Inspecting the jQuery source will reveal that the $(selector).text() that you’re familiar with, uses $.text internally:

jQuery.fn.extend({
    text: function( value ) {
        return jQuery.access( this, function( value ) {
            return value === undefined ?
                jQuery.text( this ) :
                this.empty().append( ( this[0] && this[0].ownerDocument || document ).createTextNode( value ) );
        }, null, value, arguments.length );
    },

It is an undocumented function (which means further jQuery revisions may drop it at will, without notifying you). You’ll find its definition as such:

jQuery.text = Sizzle.getText;

Sizzle.getText, in turn, is documented as “Utility function for retrieving the text value of an array of DOM nodes”. Seeing as Sizzle.getText is a documented feature, I would recommend using that rather than the jQuery shorthand, as I don’t expect jQuery to drop Sizzle any time soon.

This function, then, is the piece of code that yields the text content of a DOM node. Your sorting method is sorting DOM nodes by the alphabetical order of their text content. I don’t know why the author has decided to get the text of an array containing only one element ([a]), rather than passing the element immediately (a), which would work equally well.