Enyo control, that displays a ShareThis button. Requires use of enyo.Once (https://gist.github.com/dmikey/600ebf57cc11e085d13c) , see it in action: http://jsfiddle.net/toxigenicpoem/YE2LJ/show

enyo.ShareThis.js

(function(enyo, scope){
    
    //load share this on the page
    var loadShareThis = enyo.Once(function(callback) {
        enyo.load('//w.sharethis.com/button/buttons.js', 
            callback  
        );
    });

    var checkShareThis = function(callback) {
        //poll to see if sharethis was loaded on the page
        loadShareThis(callback);
        var pollShareThisId = setTimeout(function pollShareThis(){
            if(typeof stWidget === 'object'){
                clearTimeout(pollShareThisId);
                callback();
            }else {
                setTimeout(pollShareThis, 1000)
            };
        }, 1000);
        
    };

    //share this kind for use in other controls
    enyo.kind({
        name: 'ShareThis',
        components: [
            {name:'shareThisContainer'}
        ],
        hasExternalLoaded: false,
        observers:{
            'observeExternalLoaded': ['hasExternalLoaded']
        },
        opts: {
            "service":"sharethis",
            "url":"http://sharethis.com/3",
            "title":"sharethis",
            "type":"large",
            "text":"ShareThis" ,
            "image":"http://icons.iconarchive.com/icons/iconshock/high-detail-social/256/sharethis-icon.png",
            "summary":"this is description3"   
        },
        observeExternalLoaded: function(){
            this.opts.element = document.getElementById(this.$.shareThisContainer.id);
            stWidget.addEntry(this.opts);   
        },
        constructor: function() {
            this.inherited(arguments);
            
            var loadCallback =  enyo.bind(this, function(){
                this.set('hasExternalLoaded', true);
            });
            
            checkShareThis(loadCallback);            
        }
    });
    
}(enyo, this))