Agnostic storage adapter for HTML localStorage + Chrome sync storage

localstorage-adapter.js

var Storage;

// If this is running as a chrome extension, use chrome sync storage
if (chrome && chrome.storage && chrome.storage.sync) {
	Storage = {
		get: function (key,cb) {
			chrome.storage.sync.get(key,function(result) {
				cb(null,result && result[key]);
			});
		},
		set: function (key,val,cb) {
			var args = normalizeSetArgs(key,val,cb);
			chrome.storage.sync.set(args.data,function() {
				args.callback && args.callback();
			});
		}
	};
}
// Otherwise fall back to window.localStorage
else {
	Storage = {
		get: function (key,cb) {
			cb(null,window.localStorage.getItem(key));
		},
		set: function (key,val,cb) {
			var args = normalizeSetArgs(key,val,cb);
			_.each(args,function(v,k) {
				window.localStorage.setItem(k,v);
			});
			args.callback && args.callback();
		}
	};
}

// Assign to Mast
Mast.LocalStorage = Storage;

function normalizeSetArgs(key,val,cb) {
	// Normalize arguments
	var toStore,callback;
	if (_.isObject(key)) {
		toStore = key;
		callback = val;
	}
	else {
		toStore = {};
		toStore[key] = val;
		callback = cb;
	}
	return {
		data: toStore,
		callback: callback
	};
}