chore: edit globalThis.js to first check for globalThis

[katelynsills]

Corresponding issue (if exists):

N/A, but can create if that would be helpful.

What would you like to add/fix?

Now that globalThis is generally available on all the latest platforms, globalThis.js can be improved by first checking for the presence of globalThis.

My motivation: At Agoric, we have a secure version of JavaScript called SES. Under SES, globalThis exists, but window, self, and Function('return this')() are all undefined for security reasons. So, jss was failing for us, but by including globalThis, it will safely succeed even under our security requirements.

Todo

• Add test that verifies the modified behavior

I would be happy to add a test, but I wasn't sure what to test and where to put it. It looks like there are no unit tests for globalThis. I'm testing locally that jss works for me under SES with this change.

• Add documentation if it changes public API

[kof]

What a great PR. I think testing this is not necessary, because to test this we would have to simulate that environment and we would be mostly testing the simulation, since there isn't much logic in there.

I think what we need is to add an inline comment with exactly what you just said in the description, so that it's clear why it exists and we can merge it.

[kof]

I just looked into the current version of core-js of this, https://github.com/zloirock/core-js/blob/master/packages/core-js/internals/global.js

[katelynsills]

Ok, great! Would adding the following comment work?

Now that `globalThis` is available on most platforms (https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/globalThis#browser_compatibility) we check for `globalThis` first.

[kof]

That and also your use case with that execution environment

[katelynsills]

That and also your use case with that execution environment

That comment has been added!

[kof]

merged, thank you, will be released with the next release at some point. I aggregate a bit.

[kof]

Released in v10.6.0