jQuery.widgetのoptionのような機構

fiddle.html

<div id="hoge">
    <div class="foo"></div>
</div>

fiddle.js

/**
 * @param target Object|HTMLElement
 * @param ns String
 * @param defaultData Object
 * @return Function
 * @example

// ex1
var obj = {};
obj.data = dataPacker(obj);
obj.data("hoge", "value");

// ex2
var obj = {};
var el = document.getElementById("foo");
obj.elements = dataPacker(el);
obj.elements("fuga", ".fuga");

 */
function dataPacker(target, ns, defaultData) {
    var nsList, data, self, packer;
    
    if (!ns) {
        ns = "_dataPacker";
    }
    if (target.tagName) {
        self = target;
        target= {};
    }
    
    nsList = ns.split(".");
    data = target;
    for (var i = 0, len = nsList.length; i < len; i++) {
        data[nsList[i]] = data[nsList[i]] || {};
        data = data[nsList[i]];
    }
    packer = function(name, value) {
        var el;
        switch (arguments.length) {
            case 1:
                return data[name];
            case 2:
                if (!self) {
                    data[name] = value;
                } else {
                    el = self.querySelectorAll(value);
                    if (el) {
                        data[name] = el.length > 0 ? el : el[0];
                    } else {
                        data[name] = null;
                    }
                }
                return value;
            default:
                return data;
        }
    };
    if (defaultData) {
        for (var name in defaultData) {
            packer(name, defaultData[name]);
        }
    }
    return packer;
}

fiddle.manifest

name: dataPacker.js
description: jQuery.widgetのoptionのような機構
authors:
  - atomer
resources:
normalize_css: no