Add support for defining globals via JS scripts (wasmerio#84)

* feat: add js_modules for define global scope object

* feat: adjust type declaration, js_modules and add readme

* refactor: remove unused file and formatting

* refactor: change module name and add readme

* feat: change error message

* Rework the global scripts to work in script mode

---------

Co-authored-by: @MasatoDev <[email protected]>

build.rs

@@ -7,8 +7,18 @@ fn main() {
     // once in debug mode, and the JS scripts will be updated and pushed.
     let profile = std::env::var("PROFILE").unwrap();
     if profile == "debug" {
-        let mut dir = std::env::current_dir().unwrap();
-        dir.extend(["src", "builtins", "internal_js_modules"]);
+        let builtins_dir = std::env::current_dir().unwrap().join("src/builtins");
+
+        let dir = builtins_dir.join("internal_js_modules");
+        assert!(Command::new("npx")
+            .arg("tsc")
+            .current_dir(dir)
+            .output()
+            .unwrap()
+            .status
+            .success());
+
+        let dir = builtins_dir.join("js_globals");
         assert!(Command::new("npx")
             .arg("tsc")
             .current_dir(dir)

src/builtins/internal_js_modules.rs

@@ -1,16 +1,17 @@
+//! Here, we initialize those modules that are defined in JS, as
+//! opposed to native modules defined in Rust. The sources for
+//! these modules should be put under the internal_js_modules dir
+//! that lives next to this source file.
+//!
+//! The name of the modules will be equivalent to their path on disk,
+//! but forward slashes (/) will be changed to a colon (:) and the .js
+//! extension will be stripped. So, to create a node:buffer module,
+//! one must put the source under `internal_js_modules/node/buffer.js`.
+//!
+//! Note: Files that don't have a .js extension will be ignored.
+
 use anyhow::{anyhow, Context as _};
 use clap::builder::OsStr;
-/// Here, we initialize those modules that are defined in JS, as
-/// opposed to native modules defined in Rust. The sources for
-/// these modules should be put under the internal_js_modules dir
-/// that lives next to this source file.
-///
-/// The name of the modules will be equivalent to their path on disk,
-/// but forward slashes (/) will be changed to a colon (:) and the .js
-/// extension will be stripped. So, to create a node:buffer module,
-/// one must put the source under `internal_js_modules/node/buffer.js`.
-///
-/// Note: Files that don't have a .js extension will be ignored.
 use include_dir::{include_dir, Dir, File};
 use ion::{
     module::{Module, ModuleRequest},
@@ -47,6 +48,8 @@ fn scan_dir(cx: &Context, dir: &Dir) -> anyhow::Result<()> {
 }
 
 fn compile_and_register(cx: &Context, script_file: &File) -> anyhow::Result<()> {
+    tracing::debug!("Registering internal module at {:?}", script_file.path());
+
     let module_name = script_file
         .path()
         .to_str()

src/builtins/internal_js_modules/node/async_hooks.js

@@ -253,10 +253,7 @@ export class AsyncLocalStorage {
         return AsyncResource.bind(fn);
     }
     static snapshot() {
-        return AsyncLocalStorage.bind((
-            cb,
-            ...args
-        ) => cb(...args));
+        return AsyncLocalStorage.bind((cb, ...args) => cb(...args));
     }
 }
 export function executionAsyncId() {