smoothiecharts is not a constructor

[Fereshte Bagher Oskooei]

hello. I am trying to get started to do some charts with smoothiecharts in nodejs and have a problem.

    when I go ahead using the tutorial, after creating the canvas and

var smoothie = new SmoothieChart();
smoothie.streamTo(document.getElementById("mycanvas"));

 and the rest of the code I get the error that "smoothiechart" is not defined so I add:

           var SmoothieChart=require('smoothie');

but this time I get the error that smoothiecharts is not a constructor. can anybody help me solve this?