MMM-Rest & pimatic REST-API

I need help by my pimatic integration with the MMM-Rest Module.
In the Module docu the url returns a single Integer but my pimatic api returs a string with more informations. like this

curl http://user:user@himbeere/api/variables/dht-01.temperature
{“variable”:{“name”:“dht-01.temperature”,“readonly”:true,“type”:“attribute”,“value”:20,“unit”:“°C”},“success”:true}

what i need ist the value 20

how i can filter the response?

i have found this for an php request but i dont know how i can use it in the node_helper.js

<b>Single value from weather.temperature:</b><br />
php
   $curl = curl_init();
   curl_setopt ($curl, CURLOPT_URL, "http://demo:demo@demo.pimatic.org/api/variables/variable-set.temperature");
   curl_setopt ($curl, CURLOPT_RETURNTRANSFER, 1);

   $result = curl_exec ($curl);// curl to a variable
    curl_close ($curl);

	$result = json_decode($result, true);// decode to associative array
	$result = $result['variable']['value'];//pick desired value

	print "Temperature: ".$result;

$result = Temperature 11.4

node_helper.js

/* Magic Mirror
 * Module: MMM-Rest
 *
 * By Dirk Melchers 
 * MIT Licensed.
 */
var NodeHelper = require('node_helper');
var request = require('request');

module.exports = NodeHelper.create({
    start: function () {
        console.log(this.name + ' helper started ...');
    },

    socketNotificationReceived: function(notification, payload) {
        if (notification === 'MMM_REST_REQUEST') {
            var that = this;
            request({
                url: payload.url,
                method: 'GET'
            }, function(error, response, body) {
                // console.log("MMM_REST response:");
                if (!error && response.statusCode == 200) {
                    // console.log("send notification: "+payload.id);
                    that.sendSocketNotification('MMM_REST_RESPONSE', {
                        id: payload.id,
                        data: response
                    });
                }
            });
        }
    }
});

does anyone have an idea how i can integrate the decode in the node_helper.js?