How to use CDN link defined inside the index.html file and use them inside the ReactJS component?

Question

I am trying to use ros2djs library via CDN inside a ReactJS component.
I tried to import ros2d inside the component using suggestions available online. Those didn't work. NPM version of ros2djs called ros2d is available, but that also doesn't seem to work as the app is unable to find the module.
Therefore, I'm trying to use CDN.

CDN :

<script
  src="http://static.robotwebtools.org/ros2djs/current/ros2d.min.js"
  defer
></script>;

Tried using CDN link inside React js component. Unable to use it. Logging the ROS2D in brower console resulted in undefined.