Protect navigator access from causing a ReferenceError

[kungfooman]

Fixes: #322

Now we can properly import it in node via await import('./dist/module/src/index.mjs') aswell:

[willeastcott]

Suggested change

	const IS_CHROME = /Chrome\//.test(globalThis.navigator?.userAgent);
	const IS_CHROME = /Chrome\//.test(navigator?.userAgent || "");

[kungfooman]

It doesn't work like that in node:

(base) homepc@home-pc:~$ node
Welcome to Node.js v18.12.1.
Type ".help" for more information.
> IS_CHROME_A = /Chrome\//.test(navigator?.userAgent || "");
Uncaught ReferenceError: navigator is not defined
> IS_CHROME_B = /Chrome\//.test(globalThis.navigator?.userAgent);
false
> 

And in browsers it works aswell:

[willeastcott]

OK, yeah, I see. So I guess I was just trying to eliminate globalThis because I was concerned that it's a reasonably new addition to JS (ES2020). In the engine for example, we don't use globalThis anywhere except in the JSDoc comments. Instead, we tend to do this:

https://github.com/playcanvas/engine/blob/26a73a1fb6db893936c446a43611ff649290a27c/src/core/platform.js#L19-L20

I don't think Babel will transpile globalThis for older browsers.

All this said, this is PCUI and not the engine so it's much less likely to run in older browsers. I'm also wondering whether the IS_CHROME test is even still needed since it seems to be being used to get around some old browser problem that might not even be an issue today.

I'll approve + merge for now though.

[kungfooman]

Good points, if we run into issues, we could replace it with:

> IS_CHROME_C = typeof navigator !== 'undefined' ? /Chrome\//.test(navigator.userAgent) : false;
false

Or test if we still require this, as you said 👍