store.js

/*
## store.js by Frank Kohlhepp
## Copyright (c) 2011 - 2012 Frank Kohlhepp
## https://github.com/frankkohlhepp/store-js
## License: MIT-license
*/
(function () {
	var has = function (object, key) {
		return Object.prototype.hasOwnProperty.call(object, key);
	};
	
	var objectGetLength = function (object) {
		var count = 0;
		for (var key in object) {
			if (has(object, key)) { count++; }
		}
		
		return count;
	};
	
	var arrayIndexOf = function (array, item, from) {
		var length = array.length >>> 0;
		for (var i = (from < 0) ? Math.max(0, length + from) : from || 0; i < length; i++) {
			if (array[i] === item) { return i; }
		}
		
		return -1;
	};
	
	var arrayContains = function (array, item, from) {
		return arrayIndexOf(array, item, from) !== -1;
	};
	
	var arrayInclude = function (array, item) {
		if (!arrayContains(array, item)) { array.push(item); }
		return array;
	};
	
	var Store = this.Store = function (name, defaults, watcherSpeed) {
		this.name = name;
		this.defaults = defaults || {};
		this.watcherSpeed = watcherSpeed || 500;
		this.listeners = {};
		
		// Apply defaults
		this.applyDefaults();
	};
	
	Store.clear = function () {
		localStorage.clear();
	};
	
	Store.prototype.applyDefaults = function () {
		for (var key in this.defaults) {
			if (has(this.defaults, key) && this.get(key) === undefined) {
				this.set(key, this.defaults[key]);
			}
		}
		
		return this;
	};
	
	Store.prototype.watcher = function (force) {
		if (this.watcherTimer) {
			clearTimeout(this.watcherTimer);
		}
		
		if (objectGetLength(this.listeners) || force) {
			this.newObject = this.toObject();
			
			if (this.oldObject) {
				for (var key in this.newObject) {
					if (has(this.newObject, key) && this.newObject[key] !== this.oldObject[key]) {
						this.fireEvent(key, this.newObject[key]);
					}
				}
				
				for (var key in this.oldObject) {
					if (has(this.oldObject, key) && !has(this.newObject, key)) {
						this.fireEvent(key, this.newObject[key]);
					}
				}
			}
			
			this.oldObject = this.newObject;
			var that = this;
			this.watcherTimer = setTimeout(function () {
				that.watcher();
			}, this.watcherSpeed);
		}
		
		return this;
	};
	
	Store.prototype.get = function (name) {
		var value = localStorage.getItem("store." + this.name + "." + name);
		if (value === null) { return undefined; }
		try { return JSON.parse(value); } catch (e) { return null; }
	};
	
	Store.prototype.set = function (name, value) {
		if (value === undefined) {
			this.remove(name);
		} else {
			if (typeof value === "function") { value = null; }
			try { value = JSON.stringify(value); } catch (e) { value = null; }
			localStorage.setItem("store." + this.name + "." + name, value);
		}
		
		return this;
	};
	
	Store.prototype.remove = function (name) {
		localStorage.removeItem("store." + this.name + "." + name);
		return this.applyDefaults();
	};
	
	Store.prototype.reset = function () {
		var name = "store." + this.name + ".";
		for (var i = (localStorage.length - 1); i >= 0; i--) {
			if (localStorage.key(i).substring(0, name.length) === name) {
				localStorage.removeItem(localStorage.key(i));
			}
		}
		
		return this.applyDefaults();
	};
	
	Store.prototype.toObject = function () {
		var values = {};
		var name = "store." + this.name + ".";
		for (var i = (localStorage.length - 1); i >= 0; i--) {
			if (localStorage.key(i).substring(0, name.length) === name) {
				var key = localStorage.key(i).substring(name.length);
				var value = this.get(key);
				if (value !== undefined) { values[key] = value; }
			}
		}
		
		return values;
	};
	
	Store.prototype.fromObject = function (values, merge) {
		if (!merge) { this.reset(); }
		for (var key in values) {
			if (has(values, key)) {
				this.set(key, values[key]);
			}
		}
		
		return this;
	};
	
	Store.prototype.addEvent = function (selector, callback) {
		this.watcher(true);
		if (!this.listeners[selector]) { this.listeners[selector] = []; }
		arrayInclude(this.listeners[selector], callback);
		return this;
	};
	
	Store.prototype.removeEvent = function (selector, callback) {
		if (this.listeners[selector]) {
			for (var i = (this.listeners[selector].length - 1); i >= 0; i--) {
				if (this.listeners[selector][i] === callback) { this.listeners[selector].splice(i, 1); }
			}
			if (!this.listeners[selector].length) { delete this.listeners[selector]; }
		}
		
		return this;
	};
	
	Store.prototype.fireEvent = function (name, value) {
		var selectors = [name, "*"];
		for (var i = 0; i < selectors.length; i++) {
			var selector = selectors[i];
			if (this.listeners[selector]) {
				for (var j = 0; j < this.listeners[selector].length; j++) {
					this.listeners[selector][j](value, name, this.name);
				}
			}
		}
		
		return this;
	};
}());