[oden] Load typescript kinda

src/script.rs

@@ -1,16 +1,165 @@
 use oden_js::{
     module::loader::{ModuleLoader, ModuleSource},
-    Context, ContextRef, Result, Runtime, Value,
+    Context, ContextRef, Error, Result, Runtime, Value,
 };
+use std::cell::RefCell;
 use std::ffi::OsStr;
 use std::path::Path;
+use std::rc::Rc;
 use std::sync::mpsc::{channel, Receiver};
 
+use swc_common::{
+    self, comments::SingleThreadedComments, errors::Diagnostic, sync::Lrc, FileName, Globals, Mark,
+    SourceMap, GLOBALS,
+};
+use swc_ecma_codegen::{text_writer::JsWriter, Emitter};
+use swc_ecma_parser::{lexer::Lexer, Parser, StringInput, Syntax};
+use swc_ecma_transforms_base::{fixer::fixer, hygiene::hygiene, resolver};
+use swc_ecma_transforms_typescript::strip;
+use swc_ecma_visit::FoldWith;
+
 pub mod graphics;
 use graphics::GraphicsCommand;
 
-fn transpile_to_javascript(_path: &str, input: String) -> Result<String> {
-    Ok(input)
+struct DiagnosticCollector {
+    cell: Rc<RefCell<Vec<Diagnostic>>>,
+}
+
+impl DiagnosticCollector {
+    pub fn into_handler(self) -> swc_common::errors::Handler {
+        swc_common::errors::Handler::with_emitter(true, false, Box::new(self))
+    }
+}
+
+impl swc_common::errors::Emitter for DiagnosticCollector {
+    fn emit(&mut self, db: &swc_common::errors::DiagnosticBuilder<'_>) {
+        use std::ops::Deref;
+        self.cell.borrow_mut().push(db.deref().clone());
+    }
+}
+
+fn is_fatal_swc_diagnostic(diagnostic: &Diagnostic) -> bool {
+    use swc_common::errors::Level;
+    match diagnostic.level {
+        Level::Bug
+        | Level::Cancelled
+        | Level::FailureNote
+        | Level::Fatal
+        | Level::PhaseFatal
+        | Level::Error => true,
+        Level::Help | Level::Note | Level::Warning => false,
+    }
+}
+fn format_swc_diagnostic(source_map: &SourceMap, diagnostic: &Diagnostic) -> String {
+    if let Some(span) = &diagnostic.span.primary_span() {
+        let file_name = source_map.span_to_filename(*span);
+        let loc = source_map.lookup_char_pos(span.lo);
+        format!(
+            "{} at {}:{}:{}",
+            diagnostic.message(),
+            file_name,
+            loc.line,
+            loc.col_display + 1,
+        )
+    } else {
+        diagnostic.message()
+    }
+}
+
+fn ensure_no_fatal_swc_diagnostics<'a>(
+    name: &str,
+    source_map: &SourceMap,
+    diagnostics: impl Iterator<Item = &'a Diagnostic>,
+) -> Result<()> {
+    let fatal_diagnostics = diagnostics
+        .filter(|d| is_fatal_swc_diagnostic(d))
+        .collect::<Vec<_>>();
+    if !fatal_diagnostics.is_empty() {
+        Err(Error::ParseError(
+            name.into(),
+            fatal_diagnostics
+                .iter()
+                .map(|d| format_swc_diagnostic(source_map, d))
+                .collect::<Vec<_>>()
+                .join("\n\n"),
+        ))
+    } else {
+        Ok(())
+    }
+}
+
+fn transpile_to_javascript(path: &str, input: String) -> Result<String> {
+    // NOTE: This was taken almost verbatim from
+    //       https://github.com/swc-project/swc/blob/main/crates/swc_ecma_transforms_typescript/examples/ts_to_js.rs
+    //       This appears to be similar to what deno_ast does, but this has
+    //       the advantage of actually compiling. :P
+    let cm: Lrc<SourceMap> = Default::default();
+    let diagnostics_cell: Rc<RefCell<Vec<Diagnostic>>> = Rc::new(RefCell::new(Vec::new()));
+    let handler = DiagnosticCollector {
+        cell: diagnostics_cell.clone(),
+    }
+    .into_handler();
+
+    let fm = cm.new_source_file(FileName::Custom(path.into()), input.into());
+    let comments = SingleThreadedComments::default();
+
+    let lexer = Lexer::new(
+        Syntax::Typescript(Default::default()),
+        Default::default(),
+        StringInput::from(&*fm),
+        Some(&comments),
+    );
+
+    let mut parser = Parser::new_from(lexer);
+
+    for e in parser.take_errors() {
+        e.into_diagnostic(&handler).emit();
+    }
+
+    let module = parser
+        .parse_module()
+        .map_err(|e| e.into_diagnostic(&handler).emit())
+        .expect("failed to parse module.");
+
+    let globals = Globals::default();
+    GLOBALS.set(&globals, || {
+        let unresolved_mark = Mark::new();
+        let top_level_mark = Mark::new();
+
+        // Optionally transforms decorators here before the resolver pass
+        // as it might produce runtime declarations.
+
+        // Conduct identifier scope analysis
+        let module = module.fold_with(&mut resolver(unresolved_mark, top_level_mark, true));
+
+        // Remove typescript types
+        let module = module.fold_with(&mut strip(top_level_mark));
+
+        // Fix up any identifiers with the same name, but different contexts
+        let module = module.fold_with(&mut hygiene());
+
+        // Ensure that we have enough parenthesis.
+        let module = module.fold_with(&mut fixer(Some(&comments)));
+
+        let mut buf = vec![];
+        {
+            let mut emitter = Emitter {
+                cfg: swc_ecma_codegen::Config {
+                    minify: false,
+                    ..Default::default()
+                },
+                cm: cm.clone(),
+                comments: Some(&comments),
+                wr: JsWriter::new(cm.clone(), "\n", &mut buf, None),
+            };
+
+            emitter.emit_module(&module).unwrap();
+        }
+
+        let diagnostics = diagnostics_cell.borrow();
+        ensure_no_fatal_swc_diagnostics(path, &cm, diagnostics.iter())?;
+        Ok(String::from_utf8(buf).expect("non-utf8?"))
+    })
 }
 
 struct Loader {}