I have recently written a vanilla javaScript library to visualize Radar diagrams. It is open source and you are free to use it and contribute.

The library itself can be found in NPM https://www.npmjs.com/package/radar-diagram

run npm install radar-diagram or yarn add radar-diagram in you project to add it to your dependencies.

The demo radar can be found here https://radar.anilmaharjan.com.np/

In addition, I have used the library with ReactJs to demonstrate how it can be implemented in ReactJs.

The demo for React radar can be found here https://react-radar.anilmaharjan.com.np/

Radar plot in javascript
Radar Diagram in javascript
Video Demo