minor changes.

Signed-off-by: liuyanghejerry <liuyanghejerry@126.com>
change: use msgpack to parse and stringify JSON.

Signed-off-by: liuyanghejerry <liuyanghejerry@126.com>
add: test.js for simple unit testing.

Signed-off-by: liuyanghejerry <liuyanghejerry@126.com>