Question

This is my first jQuery plugin. Can I get some pointers? It’s currently not working…

; (function($) {

$.fn.tagCloud = function(options) {
        options = options || {};

    var maxPercent = options['maxPercent'] || 150;
    var minPercent = options['minPercent'] || 100;
    var retrieveCount = options['retrieveCount'] || function(element) { return $(element).attr('rel'); };
    var apply = options['apply'] || function(element, size) { $(element).attr('style', 'font-size:' + size + '%;'); };

    var max = null;
    var min = null;

    var tagElements = this;

    tagElements.each(function(element) {
        count = retrieveCount(element);
        max = (max == null || count > max ? count : max);
        min = (min == null || min > count ? count : min);
    });

    var multiplier = (maxPercent - minPercent) / (max - min);

    tagElements.each(function(element) {
        count = retrieveCount(count);
        size = (minPercent + (count - min) * multiplier);
        apply(element, size);
    });
}
})(jQuery);

Usage: $('a.tag').tagCloud();

Answer 1

make use of a static set of defaults instead of hard coding them. that way a user can override them withough havingto set them in the call for example:

$.fn.tagCloud.defaults = {
    maxPercent: 150,
    minPercent: 100,
    countCallback: function(element){return $(element).attr('rel');},
    applyCallback: function(element, size) { $(element).attr('style', 'font-size:' + size + '%;');}
};

And then in the very beginning of your plugin you would replace alot of those var declarations with a simple:

var o = $.extend($.fn.tagCloud.defaults, options||{});

then you would access everything with o.* or o['*'] id also make some of you logic into encapsulated methods.. i typically only want/expect to see one this.each() block for the primary logic.

Also as an aside i believe if your selector doesnt have any elements in its collection youre going to be dividing by 0 or NaN which is generally a no-no. If im correct you might want to default min/max to 1 or do a simple check to make sure that the collection length is > 0 and bail out if it isnt depending on what you want it to do.