Support for std::env::vars in nodejs target

[Thesephi]

Hi wasm-bindgen team & community,

I stumbled upon this use case just now:

• I have a function in lib.rs which iterates over the list of environment variables using std::env::vars()

• I compile successfully (with wasm-pack build --target nodejs)

• I import the generated wasm module into my Node.js script, everything runs fine except it panics as soon as it reaches the std::env::vars() part:

  

To reproduce on your local, you could:

• checkout my example project at this tag: https://github.com/dklabco/cosmos-tools/tree/discussion-std-env-vars-1
• execute make build, then make std-env-vars
• you should now see the panicking happens as I elaborate here
  • and this is the line of rust code that causes the panic

My current setups (in case it helps):

• rustc 1.60.0 (7737e0b5c 2022-04-04)
• wasm-pack 0.10.2
• Node.js v18.1.0

I tried looking up in the Discord channel, the GitHub Issues and Discussions sections, but I wasn't able to find a relevant thread. Could I have overlooked anything? Otherwise, is this "use case" justified? Is there anything worth discussing or anything I could elaborate on / help with?

Thank you in advance for your feedback & insights!

[ranile]

This has to do with the implementation in std. The nodejs flag only specifies the JS loader that is generated

You can import the node JS function for reading environment variables and call it. That should give you the environment variables