analog sensor read using Cylonjs

I am trying to read an analog sensor value using cylonjs framework.

I used this code for reading values.

var Cylon = require('cylon');

Cylon.robot({
  connections: {
    ras: { adaptor: 'raspi'}
  },

  devices: {
    sensor: { driver: 'analog-sensor', pin: 13, lowerLimit: 0, upperLimit: 1000 }
  },

  work: function(my) {
    var analogValue = 0;

    every((1).second(), function() {
      analogValue = my.sensor.analogRead();
      console.log('Analog value => ', analogValue);
    });

    my.sensor.on('lowerLimit', function(val) {
      console.log("Lower limit reached!");
      console.log('Analog value => ', val);
    });

    my.sensor.on('upperLimit', function(val) {
      console.log("Upper limit reached!");
      console.log('Analog value => ', val);
    });
  }
}).start();

Basically this is default arduino LDR program. When I try to execute this, I am getting this.

my_folder/node_modules/cylon-gpio/lib/analog-sensor.js:94
this.connection.analogRead(this.pin, function(err, readVal) { ^

TypeError: this.connection.analogRead is not a function

I know rpi is not directly supporting analog pins, How I can modify this javascript to read analog values.

I just started cylonjs, so any help or guide would be greatly appreciated.

Thanks in advance.