shell.js: Handle if location object does not exist

[disjukr]

When compiling with the options introduced in this comment, the ENVIRONMENT_IS_WORKER value is set to true.
In Deno, the value of self.location is undefined when the deno run command is executed without the --location CLI argument.
In the scenario of creating the Deno library, it is difficult to tell the library user to input the --location CLI argument, so I modified it to handle fallback at this level.

[kripken]

Thanks for the PR!

In general this sounds good. Please take a look at the CI errors though, and let us know if you can't figure them out.

One possibility is that ?. notation may not be supported in one of our tools (I don't think we use it anywhere atm). But that's just a guess.

[kleisauke]

Regarding the ?. notation, this is being tracked in issue #15827.

[kripken]

I looked into this a little more now. It seems like node also does not define location (or self for that matter). We work around that here:

emscripten/src/worker.js

Lines 31 to 37 in 1056be2

	Object.assign(global, {
	self: global,
	require: require,
	Module: Module,
	location: {
	href: __filename
	},

@disjukr is the problem with Deno also just when using pthreads? If so, then I think working around it in worker.js like we do for node might make sense.

[disjukr]

@kripken

@disjukr is the problem with Deno also just when using pthreads? If so, then I think working around it in worker.js like we do for node might make sense.

In my situation, when the -pthread option is attached, an error occurs saying that it cannot be used with the --shared-memory option, and the build fails.

wasm-ld: error: --shared-memory is disallowed by enc/webp_enc.o because it was not compiled with 'atomics' or 'bulk-memory' features.

I'm not familiar with c/cpp so I can't narrow down the reproduction path properly, but when I built a very simple pthread example, the ENVIRONMENT_IS_WORKER variable is set to false, so the branch accessing self.location.href does not run.

[disjukr]

Oh sorry. I noticed that I accidentally included the -s ENVIRONMENT=$(ENVIRONMENT) (and that expanded as -s ENVIRONMENT=worker).
I tried to build without this option and the branch that access self.location.href never runs.