It is really simple JSON-RPC :) Now, only client but server coming soon...
Simply use npm to install it
npm install simple-jsonrpc
or download the code from the repo and stick it in your project folder.
var jsonrpc = require('simple-jsonrpc');
var client = jsonrpc.client("https://my-json-rpc-server/path-to-something/");
client.call('add', [1, 2], function (result) {
console.log(result);
});