Render Normal JavaScript in React

So I'm new to react and I'm trying to understand how non-react code and react code can interact.

So for example, let's say I have a library which draws a circle in a DOM element with syntax like this: c = new Circle('#container')

and as soon as that code is executed, a circle is drawn in the DOM element with an id of container.

If I wanted to create a React component based off of this, how would I go about it? This is what I had in mind:

var circ = React.createClass({

    componentDidMount: function(){
      c = new Circle('#container')
    },

    render: function(){
      return (
        <div id="container"></div>
    );
   }

});

Is this acceptable, or is there a better way to go about this?