javaScript.closureCacheFn.js - to cache fns with closure, privacy of cache and nextId improved.

javaScript.closureCacheFn.js

var store = (function () {
    var nextId = 1,
        cache = {};
    return {
        addFn: function (fn) {
            if (!fn.id) {
                fn.id = nextId;
                nextId += 1;
                return !!(cache[fn.id] = fn);
            } else {
                return false;
            }
        },
        getCache: function (id) {
            return cache[id] ? cache[id] : cache;
        },
        getLength: function () {
            return nextId - 1;
        }
    };
})();


//test
var testFn = function (aa) {
    console.log('test only');
};

console.log(store.addFn(testFn));
console.log(store.addFn(function (aa) {
    console.log('test only');
}));
console.log(store.getCache());
console.log(store.getLength());