POC of using clap in NodeJS apps

[jonathanmorley]

Here is a POC of using clap in a NodeJS app: https://github.com/clap-rs/clap/compare/master...jonathanmorley:nodejs-wasm?expand=1.

Some comments:

1. It uses YAML-parsing, which I understand is deprecated and potentially being refactored into another crate. The runtime-parsing appeared to lend itself well to this style of CLI-definition though.
2. wasm-bindgen has some limitations in what it expects as exportable objects. Notably, it doesn't allow lifetimes or type parameters, which means that I had to make a couple of functions that accepted Strings instead of Keys.
3. OsString is not serde serializable outside of unix/windows.
4. The removal of forbid_unsafe is actually not necessary, its only used for the console.log statements.
5. The serde serialization was an attempt to provide ArgMatches as a JSON object back to the caller, this did not prove as useful as I had hoped because of the hashing of keys into ids.

I'm interested in hearing people's thoughts on this idea.

Relevant issues:

• 3.0.0 fails to compile on wasm32-unknown-unknown #2198
• Compilation failure under rust nightly webassembly target #1132

[epage]

What would you need from clap to make this a crate on top of it and clap_serde?

Being separate will make it easier to document wasm-specific needs and make it easier to keep the wasm-specific costs to just the wasm support (e.g. we don't want to force a serde dependency on all clap users)

Note that most of the use of Serialize is something we won't be able to accept because its exposing implementation details. We'll need custom Serialize implementations anyways, which can live as easily outside of clap as inside of it.