js lookup

gistfile1.js

var data {
   id_1: true,
   id_2: true,
   id_3: true
};

var lookup = function(dict) {
	return function(key) {
		return dict[key];
	};
};


var myLookup = lookup(data);

myLookup('id_1'); // true
myLookup('id_2'); // true
myLookup('id_100000'); // undefined