Function update

test/store_test.js:60–70

(key, val, s)

        get(key, expect, s);
    }
    function update(key, val, s) {
        if (typeof key === 'string' || val !== undefined) {
            ok((s || store)(key, val) != null, "update value for '"+key+"'");
            get(key, val, s);
        } else {
            equal((s || store)(key), true, 'update all values in '+key);
            for (var k in key) {
                get(k, key[k], s);
            }
        }
    }
    function transact(key, fn, alt, s) {
        var ret = (s || store)(key, fn, alt);
        strictEqual(ret, s || store, "transact should return this");