Hi Roel,

Thank you for the suggestion!

It wasn't really meant as a training tool. But in case anyone tries to learn from it, the client-side part of the component is here:

https://github.com/jkruse/googlemaps...r/src/index.js

You should not try to read the JavaScript that's on the demo site (https://www.kruse-net.dk/googlemaps/...eMaps/index.js).

I always write modern EcmaScript these days, and use build tools to transpile that to something that runs in a browser. I had a very short presentation on it at Scanduc (you can see it here, but Sture had used up almost all my time, so I had to skip a lot of the explaining: https://www.youtube.com/watch?v=-YL0hcFpPMc). That's also where the sourcemap comes from, it's generated by those build tools. If you open the demo site in Chrome, hit F12, go to "Sources" and look under "webpack://" you can actually see the original source file there, even though it's not on the demo site. And more, you can set breakpoints in it and step through it. That's what the sourcemap does, it maps the transpiled, minified JavaScript code back to the original EcmaScript code.