key shared values store

Filehandler.js

module.exports = (function (o) {
		//the actual object
		var cache = {};
		
		function Filehandler (o) {
				if (!o.deleter || !o.loader) {
					throw new Error("Delete or Load callback was not passed");
				}

				this.loader = o.loader;
				this.deleter = o.deleter;

				if (o.onchange) {
					this.onchange = o.onchange;
				} else {
					this.onchange = function () {};
				}

			};

		Filehandler.prototype.setStatic = function (arr) {
			this.setDynamic('static', arr);
		};

		Filehandler.prototype.setDynamic = function (key, arr) {
			var toLoad = [],
				toDelete = [];

			//remove file for that key
			$.each(cache, function (i, files) {
				var id = files.indexOf(key);
				if (id != -1) files.splice(id, 1);
			});

			//insert the new ones
			$.each(arr, function (i, file) {
				if (file in cache) {
					cache[file].push(key);
				} else {
					toLoad.push(file);
					cache[file] = [key];
				}
			});
			toDelete = collectDeletes.call(this);

			if (toLoad.length > 0) {
				this.loader.call(this.loader, toLoad);
			}
			if (toDelete.length > 0) {
				this.deleter.call(this.deleter, toDelete);
			}
			if (toDelete.length > 0 || toLoad.length > 0) {
				this.onchange.call(this.onchange);
			}
		}

		function collectDeletes() {
			var toDelete = [];

			$.each(cache, function (file, ids) {
				if (ids.length === 0) {
					toDelete.push(file);
					delete cache[file];
				}
			});

			return toDelete;
		}
		return new Filehandler(o);
});

var Filehandler = require('Filehandler');
//Usage
var handler = Filehandler({
	loader: function (files) {
		console.log('load', files);
	},
	deleter: function (files) {
		console.log('delete', files)
	},
	onchange: function () {

	}
});
var handler2 = Filehandler({
	loader: function (files) {
		console.log('load2', files);
	},
	deleter: function (files) {
		console.log('delete2', files)
	}
});
handler.setDynamic('banane', [3, 4, 5, 6]);
handler.setStatic([8, 9, 10]);
handler.setStatic([9]);
handler.setDynamic('apfel', [3, 6, 7, 8]);
handler.setDynamic('banane', [2]);


handler2.setDynamic('üftz', [1, 2, 3, 4, 5, 6, 7, 8, 9]);