feat: add source_map_file option for emit (#244)

src/emit.rs

@@ -25,6 +25,8 @@ pub enum SourceMapOption {
 pub struct EmitOptions {
   /// How and if source maps should be generated.
   pub source_map: SourceMapOption,
+  /// The `"file"` field of the generated source map.
+  pub source_map_file: Option<String>,
   /// Whether to inline the source contents in the source map. Defaults to `true`.
   pub inline_sources: bool,
   /// Whether to keep comments in the output. Defaults to `false`.
@@ -35,6 +37,7 @@ impl Default for EmitOptions {
   fn default() -> Self {
     EmitOptions {
       source_map: SourceMapOption::default(),
+      source_map_file: None,
       inline_sources: true,
       keep_comments: false,
     }
@@ -103,8 +106,15 @@ pub fn emit(
     let source_map_config = SourceMapConfig {
       inline_sources: emit_options.inline_sources,
     };
+    let mut source_map = source_map.build_source_map_with_config(
+      &src_map_buf,
+      None,
+      source_map_config,
+    );
+    if let Some(file) = &emit_options.source_map_file {
+      source_map.set_file(Some(file.to_string()));
+    }
     source_map
-      .build_source_map_with_config(&src_map_buf, None, source_map_config)
       .to_writer(&mut buf)
       .map_err(|e| EmitError::SourceMap(e.into()))?;
 

src/transpiling/mod.rs

@@ -1511,6 +1511,43 @@ const a = _jsx(Foo, {
     );
   }
 
+  #[test]
+  fn test_source_map_with_file() {
+    let specifier =
+      ModuleSpecifier::parse("https://deno.land/x/mod.tsx").unwrap();
+    let source = r#"{ const foo = "bar"; };"#;
+    let module = parse_module(ParseParams {
+      specifier,
+      text_info: SourceTextInfo::from_string(source.to_string()),
+      media_type: MediaType::Tsx,
+      capture_tokens: false,
+      maybe_syntax: None,
+      scope_analysis: false,
+    })
+    .unwrap();
+    let emit_options = EmitOptions {
+      source_map: SourceMapOption::Separate,
+      source_map_file: Some("mod.tsx".to_owned()),
+      ..Default::default()
+    };
+    let emit_result = module
+      .transpile(&TranspileOptions::default(), &emit_options)
+      .unwrap()
+      .into_source();
+    assert_eq!(
+      &emit_result.text,
+      r#"{
+  const foo = "bar";
+}"#
+    );
+    assert_eq!(
+      emit_result.source_map.as_deref(),
+      Some(
+        r#"{"version":3,"file":"mod.tsx","sources":["https://deno.land/x/mod.tsx"],"sourcesContent":["{ const foo = \"bar\"; };"],"names":[],"mappings":"AAAA;EAAE,MAAM,MAAM;AAAO"}"#
+      )
+    );
+  }
+
   #[test]
   fn test_no_source_map() {
     let specifier =