feat(napi/transform): add lang option to change source type (#6309)

part of #6274 and #6156

```
    /// Treat the source text as `js`, `jsx`, `ts`, or `tsx`.
    #[napi(ts_type = "'js' | 'jsx' | 'ts' | 'tsx'")]
    pub lang: Option<String>,
```

crates/oxc/src/napi/transform.rs

@@ -57,6 +57,10 @@ pub struct TransformOptions {
     #[napi(ts_type = "'script' | 'module' | 'unambiguous' | undefined")]
     pub source_type: Option<String>,
 
+    /// Treat the source text as `js`, `jsx`, `ts`, or `tsx`.
+    #[napi(ts_type = "'js' | 'jsx' | 'ts' | 'tsx'")]
+    pub lang: Option<String>,
+
     /// The current working directory. Used to resolve relative paths in other
     /// options.
     pub cwd: Option<String>,

napi/transform/index.d.ts

@@ -182,6 +182,8 @@ export declare function transform(filename: string, sourceText: string, options?
  */
 export interface TransformOptions {
   sourceType?: 'script' | 'module' | 'unambiguous' | undefined
+  /** Treat the source text as `js`, `jsx`, `ts`, or `tsx`. */
+  lang?: 'js' | 'jsx' | 'ts' | 'tsx'
   /**
    * The current working directory. Used to resolve relative paths in other
    * options.

napi/transform/src/errors.rs

@@ -1,4 +1,4 @@
-use std::sync::Arc;
+use std::{path::Path, sync::Arc};
 
 use oxc::{
     diagnostics::{Error, NamedSource, OxcDiagnostic},
@@ -6,7 +6,7 @@ use oxc::{
 };
 
 pub fn wrap_diagnostics(
-    filename: &str,
+    filename: &Path,
     source_type: SourceType,
     source_text: &str,
     errors: Vec<OxcDiagnostic>,
@@ -28,7 +28,8 @@ pub fn wrap_diagnostics(
             }
         };
 
-        let ns = NamedSource::new(filename, source_text.to_string()).with_language(lang);
+        let ns = NamedSource::new(filename.to_string_lossy(), source_text.to_string())
+            .with_language(lang);
         Arc::new(ns)
     };
 

napi/transform/src/isolated_declaration.rs

@@ -1,3 +1,5 @@
+use std::path::Path;
+
 use napi_derive::napi;
 
 use oxc::{
@@ -22,7 +24,8 @@ pub fn isolated_declaration(
     source_text: String,
     options: Option<IsolatedDeclarationsOptions>,
 ) -> IsolatedDeclarationsResult {
-    let source_type = SourceType::from_path(&filename).unwrap_or_default().with_typescript(true);
+    let source_path = Path::new(&filename);
+    let source_type = SourceType::from_path(source_path).unwrap_or_default().with_typescript(true);
     let allocator = Allocator::default();
     let options = options.unwrap_or_default();
 
@@ -49,7 +52,7 @@ pub fn isolated_declaration(
     let codegen_ret = codegen.build(&transformed_ret.program);
 
     let errors = ret.errors.into_iter().chain(transformed_ret.errors).collect();
-    let errors = wrap_diagnostics(&filename, source_type, &source_text, errors);
+    let errors = wrap_diagnostics(source_path, source_type, &source_text, errors);
 
     IsolatedDeclarationsResult {
         code: codegen_ret.source_text,

napi/transform/src/transformer.rs

@@ -140,22 +140,35 @@ pub fn transform(
     options: Option<TransformOptions>,
 ) -> TransformResult {
     let source_path = Path::new(&filename);
-    let source_type = {
-        let mut source_type = SourceType::from_path(source_path).unwrap_or_default();
-        // Force `script` or `module`
-        match options.as_ref().and_then(|options| options.source_type.as_deref()) {
-            Some("script") => source_type = source_type.with_script(true),
-            Some("module") => source_type = source_type.with_module(true),
-            _ => {}
+
+    let source_type = match options.as_ref().and_then(|options| options.lang.as_deref()) {
+        Some("js") => SourceType::mjs(),
+        Some("jsx") => SourceType::jsx(),
+        Some("ts") => SourceType::ts(),
+        Some("tsx") => SourceType::tsx(),
+        Some(lang) => {
+            return TransformResult {
+                errors: vec![format!("Incorrect lang '{lang}'")],
+                ..Default::default()
+            }
+        }
+        None => {
+            let mut source_type = SourceType::from_path(source_path).unwrap_or_default();
+            // Force `script` or `module`
+            match options.as_ref().and_then(|options| options.source_type.as_deref()) {
+                Some("script") => source_type = source_type.with_script(true),
+                Some("module") => source_type = source_type.with_module(true),
+                _ => {}
+            }
+            source_type
         }
-        source_type
     };
 
     let mut compiler = match Compiler::new(options) {
         Ok(compiler) => compiler,
         Err(errors) => {
             return TransformResult {
-                errors: wrap_diagnostics(&filename, source_type, &source_text, errors),
+                errors: wrap_diagnostics(source_path, source_type, &source_text, errors),
                 ..Default::default()
             }
         }
@@ -167,6 +180,6 @@ pub fn transform(
         map: compiler.printed_sourcemap,
         declaration: compiler.declaration,
         declaration_map: compiler.declaration_map,
-        errors: wrap_diagnostics(&filename, source_type, &source_text, compiler.errors),
+        errors: wrap_diagnostics(source_path, source_type, &source_text, compiler.errors),
     }
 }

napi/transform/test/id.test.mjs

@@ -17,7 +17,7 @@ describe('isolated declaration', () => {
 
   it('matches output', () => {
     const ret = oxc.isolatedDeclaration('test.ts', code, { sourcemap: true });
-    assert(ret, {
+    assert.deepEqual(ret, {
       code: '/**\n' +
         '* jsdoc 1\n' +
         '*/\n' +
@@ -28,12 +28,13 @@ describe('isolated declaration', () => {
         '\tfoo: string;\n' +
         '}\n',
       map: {
-        mappings: ';;;AAIA,OAAO,cAAM,EAAE;;;;CAIb;AACD',
+        mappings: ';;;AAIE,OAAO,cAAM,EAAE;;;;CAIb;AACD',
         names: [],
         sources: ['test.ts'],
         sourcesContent: [code],
         version: 3,
       },
+      errors: [],
     });
   });
 });

napi/transform/test/transform.test.mjs

@@ -7,8 +7,9 @@ describe('transform', () => {
 
   it('matches output', () => {
     const ret = oxc.transform('test.ts', code, { sourcemap: true });
-    assert(ret, {
+    assert.deepEqual(ret, {
       code: 'class A {}\n',
+      errors: [],
       map: {
         mappings: 'AAAA,MAAM,EAAK,CAAE',
         names: [],
@@ -18,6 +19,11 @@ describe('transform', () => {
       },
     });
   });
+
+  it('lang', () => {
+    const ret = oxc.transform('test.vue', code, { lang: 'ts' });
+    assert.equal(ret.code, 'class A {}\n');
+  });
 });
 
 describe('react refresh plugin', () => {
@@ -29,8 +35,9 @@ describe('react refresh plugin', () => {
 
   it('matches output', () => {
     const ret = oxc.transform('test.tsx', code, { jsx: { refresh: {} } });
-    assert(ret, {
-      code: 'var _s = $RefreshSig$();\n' +
+    assert.equal(
+      ret.code,
+      'var _s = $RefreshSig$();\n' +
         'import { useState } from "react";\n' +
         'import { jsxs as _jsxs } from "react/jsx-runtime";\n' +
         'export const App = () => {\n' +
@@ -45,7 +52,7 @@ describe('react refresh plugin', () => {
         '_c = App;\n' +
         'var _c;\n' +
         '$RefreshReg$(_c, "App");\n',
-    });
+    );
   });
 });
 
@@ -58,10 +65,8 @@ describe('define plugin', () => {
         'process.env.NODE_ENV': 'false',
       },
     });
-    assert(ret, {
-      // TODO: should be constant folded
-      code: 'if (false === "production") {\n\tfoo;\n}\n',
-    });
+    // TODO: should be constant folded
+    assert.equal(ret.code, 'if (false === "production") {\n\tfoo;\n}\n');
   });
 });
 
@@ -70,12 +75,10 @@ describe('inject plugin', () => {
 
   it('matches output', () => {
     const ret = oxc.transform('test.tsx', code, {
-      define: {
-        'process.env.NODE_ENV': 'false',
+      inject: {
+        'Object.assign': 'foo',
       },
     });
-    assert(ret, {
-      code: 'import $inject_Object_assign from "foo";\nlet _ = $inject_Object_assign;\n',
-    });
+    assert.equal(ret.code, 'import $inject_Object_assign from "foo";\nlet _ = $inject_Object_assign;\n');
   });
 });