This message was posted on behalf of Intel Corporation
If you are using the Arduino expansion board with your Edison module, then there is no need to use an external ADC since the Arduino expansion board already has one. However, if you have a different setup, I recommend you to use the MRAA library to handle the I2C interface of your ADC module. In the following site you will find the MRAA API for Nodejs where there is additional information about how you can handle the I2C interface and which methods you can use. You will also find useful examples about how to use the MRAA library: https://github.com/intel-iot-devkit/mraa
I hope you find this information helpful.