feat(swc, swc_ecma_transofmrs_module): added outFileExtension module …

…option

crates/swc/src/config/mod.rs

@@ -1400,22 +1400,39 @@ impl ModuleConfig {
 
         let base_url = base_url.to_path_buf();
         let resolver = match config {
-            None => build_resolver(base_url, paths, false),
+            None => build_resolver(base_url, paths, false, &"js".to_string()),
             Some(ModuleConfig::Es6(config)) | Some(ModuleConfig::NodeNext(config)) => {
-                build_resolver(base_url, paths, config.resolve_fully)
-            }
-            Some(ModuleConfig::CommonJs(config)) => {
-                build_resolver(base_url, paths, config.resolve_fully)
-            }
-            Some(ModuleConfig::Umd(config)) => {
-                build_resolver(base_url, paths, config.config.resolve_fully)
-            }
-            Some(ModuleConfig::Amd(config)) => {
-                build_resolver(base_url, paths, config.config.resolve_fully)
-            }
-            Some(ModuleConfig::SystemJs(config)) => {
-                build_resolver(base_url, paths, config.resolve_fully)
+                build_resolver(
+                    base_url,
+                    paths,
+                    config.resolve_fully,
+                    &config.config.out_file_extension,
+                )
             }
+            Some(ModuleConfig::CommonJs(config)) => build_resolver(
+                base_url,
+                paths,
+                config.resolve_fully,
+                &config.out_file_extension,
+            ),
+            Some(ModuleConfig::Umd(config)) => build_resolver(
+                base_url,
+                paths,
+                config.config.resolve_fully,
+                &config.config.out_file_extension,
+            ),
+            Some(ModuleConfig::Amd(config)) => build_resolver(
+                base_url,
+                paths,
+                config.config.resolve_fully,
+                &config.config.out_file_extension,
+            ),
+            Some(ModuleConfig::SystemJs(config)) => build_resolver(
+                base_url,
+                paths,
+                config.resolve_fully,
+                &config.config.out_file_extension,
+            ),
         };
 
         Some((base, resolver))
@@ -1733,6 +1750,7 @@ fn build_resolver(
     mut base_url: PathBuf,
     paths: CompiledPaths,
     resolve_fully: bool,
+    file_extension: &String,
 ) -> SwcImportResolver {
     static CACHE: Lazy<DashMap<(PathBuf, CompiledPaths, bool), SwcImportResolver, ARandomState>> =
         Lazy::new(Default::default);
@@ -1772,6 +1790,7 @@ fn build_resolver(
             swc_ecma_transforms::modules::path::Config {
                 base_dir: Some(base_url.clone()),
                 resolve_fully,
+                file_extension: file_extension.to_owned(),
             },
         );
         Arc::new(r)

crates/swc_ecma_transforms_module/src/lib.rs

@@ -5,6 +5,7 @@
 
 use serde::{Deserialize, Serialize};
 use swc_common::{Span, SyntaxContext};
+use util::Config;
 
 pub use self::{amd::amd, common_js::common_js, system_js::system_js, umd::umd};
 
@@ -26,6 +27,8 @@ pub mod umd;
 pub struct EsModuleConfig {
     #[serde(default)]
     pub resolve_fully: bool,
+    #[serde(flatten, default)]
+    pub config: Config,
 }
 
 type SpanCtx = (Span, SyntaxContext);

crates/swc_ecma_transforms_module/src/path.rs

@@ -17,6 +17,8 @@ use swc_ecma_loader::resolve::{Resolution, Resolve};
 use swc_ecma_utils::{quote_ident, ExprFactory};
 use tracing::{debug, info, warn, Level};
 
+use crate::util::default_js_ext;
+
 #[derive(Default)]
 pub enum Resolver {
     Real {
@@ -96,10 +98,21 @@ where
     config: Config,
 }
 
-#[derive(Debug, Clone, Default)]
+#[derive(Debug, Clone)]
 pub struct Config {
     pub base_dir: Option<PathBuf>,
     pub resolve_fully: bool,
+    pub file_extension: String,
+}
+
+impl Default for Config {
+    fn default() -> Config {
+        Config {
+            file_extension: default_js_ext(),
+            resolve_fully: bool::default(),
+            base_dir: Option::default(),
+        }
+    }
 }
 
 impl<R> NodeImportResolver<R>
@@ -162,13 +175,13 @@ where
             };
 
             let is_resolved_as_non_js = if let Some(ext) = target_path.extension() {
-                ext != "js"
+                ext.to_string_lossy() != self.config.file_extension
             } else {
                 false
             };
 
             let is_resolved_as_js = if let Some(ext) = target_path.extension() {
-                ext == "js"
+                ext.to_string_lossy() == self.config.file_extension
             } else {
                 false
             };
@@ -191,27 +204,30 @@ where
                 // Resolved: `./foo/index.js`
 
                 if self.config.resolve_fully {
-                    target_path.set_file_name("index.js");
+                    target_path.set_file_name(format!("index.{}", self.config.file_extension));
                 } else {
                     target_path.set_file_name("index");
                 }
-            } else if is_resolved_as_index && is_resolved_as_js && orig_filename != "index.js" {
+            } else if is_resolved_as_index
+                && is_resolved_as_js
+                && orig_filename != format!("index{}", self.config.file_extension)
+            {
                 // Import: `./foo`
                 // Resolved: `./foo/index.js`
 
                 target_path.pop();
             } else if is_resolved_as_non_js && self.config.resolve_fully && file_stem_matches {
-                target_path.set_extension("js");
+                target_path.set_extension(self.config.file_extension.clone());
             } else if !is_resolved_as_js && !is_resolved_as_index && !is_exact {
                 target_path.set_file_name(orig_filename);
             } else if is_resolved_as_non_js && is_exact {
                 if let Some(ext) = Path::new(orig_filename).extension() {
                     target_path.set_extension(ext);
                 } else {
-                    target_path.set_extension("js");
+                    target_path.set_extension(self.config.file_extension.clone());
                 }
             } else if self.config.resolve_fully && is_resolved_as_non_js {
-                target_path.set_extension("js");
+                target_path.set_extension(self.config.file_extension.clone());
             } else if is_resolved_as_non_js && is_resolved_as_index {
                 if orig_filename == "index" {
                     target_path.set_extension("");

crates/swc_ecma_transforms_module/src/system_js.rs

@@ -8,6 +8,7 @@ use swc_ecma_utils::{
 };
 use swc_ecma_visit::{fold_pass, standard_only_fold, Fold, FoldWith, VisitWith};
 
+pub use super::util::Config as InnerConfig;
 use crate::{
     path::Resolver,
     top_level_this::top_level_this,
@@ -21,6 +22,9 @@ pub struct Config {
 
     #[serde(default)]
     pub resolve_fully: bool,
+
+    #[serde(flatten, default)]
+    pub config: InnerConfig,
 }
 
 struct SystemJs {

crates/swc_ecma_transforms_module/src/util.rs

@@ -46,6 +46,13 @@ pub struct Config {
 
     #[serde(default)]
     pub resolve_fully: bool,
+
+    #[serde(default = "default_js_ext")]
+    pub out_file_extension: String,
+}
+
+pub fn default_js_ext() -> String {
+    "js".to_string()
 }
 
 impl Default for Config {
@@ -61,6 +68,7 @@ impl Default for Config {
             ignore_dynamic: false,
             preserve_import_meta: false,
             resolve_fully: false,
+            out_file_extension: "js".to_string(),
         }
     }
 }

crates/swc_ecma_transforms_module/tests/path_node.rs

@@ -11,6 +11,7 @@ use swc_ecma_parser::Syntax;
 use swc_ecma_transforms_module::{
     path::{ImportResolver, NodeImportResolver},
     rewriter::import_rewriter,
+    util::default_js_ext,
 };
 use swc_ecma_transforms_testing::{test_fixture, FixtureTestConfig};
 use testing::run_test2;
@@ -106,6 +107,7 @@ fn paths_resolver(base_dir: &Path, rules: Vec<(String, Vec<String>)>) -> JscPath
         swc_ecma_transforms_module::path::Config {
             base_dir: Some(base_dir),
             resolve_fully: true,
+            file_extension: default_js_ext(),
         },
     )
 }