Node's fs APIs resolve relative paths relative to the current working directory:
https://nodejs.org/api/fs.html#fs_file_paths
This creates a problem if you try to require the wasm-bindgen-generated
JavaScript from a different directory. For example, if you have
build/foo.js
build/foo_bg.js
build/foo_bg.wasm
and another script, script/index.js, that requires build/foo.js. We can instead
use __dirname to get the correct path to the file.
Nowadays the compile times are mitigated with incremental compilation and
otherwise it's much more ergonomic to run only one test if they're all in the
same suite.
As soon as we've removed unneeded exports immediately run a gc pass to ensure
that we don't bind functions in JS that don't actually end up getting needed.
This commit starts wasm-bindgen down the path of supporting closures. We
discussed this at the recent Rust All-Hands but I ended up needing to pretty
significantly scale back the ambitions of what closures are supported. This
commit is just the initial support and provides only a small amount of support
but will hopefully provide a good basis for future implementations.
Specifically this commit adds support for passing `&Fn(...)` to an *imported
function*, but nothing elese. The `&Fn` type can have any lifetime and the JS
object is invalidated as soon as the import returns. The arguments and return
value of `Fn` must currently implement the `WasmAbi` trait, aka they can't
require any conversions like strings/types/etc.
I'd like to soon expand this to `&mut FnMut` as well as `'static` closures that
can be passed around for a long time in JS, but for now I'm putting that off
until later. I'm not currently sure how to implement richer argument types, but
hopefully that can be figured out at some point!
