Cannot call a javascript function from HTML file in codesandbox.io. ??!!!

I was a bit surprised to see that you cannot reference a javascript function using a Vanilla sandbox using codesandbox.io site. Upon googling a bit here is what I found:

 https://github.com/codesandbox/codesandbox-client/issues/1502 

Here is the working sandbox where we can call a javascript function from an HTML file.

https://codesandbox.io/s/sleepy-sunset-w0wds?file=/src/index.js

Here is the explanation provided by the codesandbox.io folks on it:

k, so the explanation is that in the vanilla template / parcel environment we're doing module bundling, handling src/index.js as a module. Because modules are evaluated in their own (private) scope, if you want to access from html something inside the module, you can put it on the browser's global scope, which is window.

Alternatively, you can use the static template / environment, where we don't do any bundling, like https://codesandbox.io/s/quirky-flower-rm20y (but then you lose the ability to require / import).