Location Hash Wrapper

location_hash.js

var LocationHash = (function(ev){
	var hash, changed = [];

	function read_hash(){
		var list = location.hash.substr(1).split('&');
		hash = {};
		
		for (var i = 0, pair; pair = list[i]; i++){
			var split = pair.split('=');
			
			if (split.length){
				var value = split[1].split(',');

				hash[split[0]] = value.length > 1 ? value : value[0];
			}
		}
		
		for (var i = 0, cb; cb = changed[i]; i++)
			cb();
	}

	function build_param_string(type, obj){
		var values = [];
		obj = obj || hash;

		for (var i in obj){
			var value = obj[i];
			var sep = '=';

			if (type == 'h'){
				values.push(i + sep + (value.join ? value.join(',') : value));

			} else {
				if (!value.join)
					value = [value];
				else
					sep = '[]=';

				for (var j = 0, val; val = value[j]; j++)
					values.push(i + sep + val);
			}
		}

		return values.join('&');
	}

	ev(window).on('hashchange', read_hash);
        read_hash();

	return {
		params:function(type){ return build_param_string(type); },
		changed:function(callback){ changed.push(callback); },

		build:function(obj, type){ return build_param_string(type || 'q', obj); },

		get:function(key){ return hash[key]; },
		set:function(values){
			for (var key in values){
				var value = values[key];

				if (value == undefined)
					delete hash[key];
				else
					hash[key] = value;
			}

			location.hash = build_param_string('h');
		}
	};
}(_CHANGE_ME_));

Added an external method LocationHash.build which will build a query string (or 'hash string') from an object.