Forward useDefineForClassFields to swc

packages/core/integration-tests/test/integration/decorators-useDefineForClassFields/index.ts

@@ -0,0 +1,24 @@
+class LoggerClass {
+  @logger()
+  foo = 5;
+}
+
+function logger() {
+  return function (proto, originalKey) {
+    const privateKey = `__${originalKey}`;
+    Object.defineProperty(proto, originalKey, {
+      get() {
+        output(`${originalKey} ${this[privateKey]}`);
+        return this[privateKey];
+      },
+      set(value) {
+        this[privateKey] = 10 + value;
+      },
+    });
+  };
+}
+
+const instance = new LoggerClass();
+instance.foo;
+instance.foo = 6;
+instance.foo;

packages/core/integration-tests/test/integration/decorators-useDefineForClassFields/tsconfig.json

@@ -0,0 +1,6 @@
+{
+  "compilerOptions": {
+    "experimentalDecorators": true,
+    "useDefineForClassFields": false
+  }
+}

packages/core/integration-tests/test/transpilation.js

@@ -297,6 +297,24 @@ describe('transpilation', function () {
     ]);
   });
 
+  it('should support enabling decorators and setting useDefineForClassFields in tsconfig.json', async function () {
+    let b = await bundle(
+      path.join(
+        __dirname,
+        '/integration/decorators-useDefineForClassFields/index.ts',
+      ),
+    );
+
+    let output = [];
+    await run(b, {
+      output(...o) {
+        output.push(...o);
+      },
+    });
+
+    assert.deepEqual(output, ['foo 15', 'foo 16']);
+  });
+
   it('should support transpiling optional chaining', async function () {
     let b = await bundle(
       path.join(__dirname, '/integration/babel-optional-chaining/index.js'),

packages/transformers/js/core/Cargo.toml

@@ -9,7 +9,7 @@ crate-type = ["rlib"]
 
 [dependencies]
 swc_ecmascript = { version = "0.157.0", features = ["parser", "transforms", "module", "optimization", "react", "typescript", "utils", "visit", "codegen", "utils", "preset_env"] }
-swc_common = { version = "0.18.2", features = ["tty-emitter", "sourcemap"] }
+swc_common = { version = "0.18.5", features = ["tty-emitter", "sourcemap"] }
 swc_atoms = "0.2.11"
 indoc = "1.0.3"
 serde = "1.0.123"

packages/transformers/js/core/src/lib.rs

@@ -81,6 +81,7 @@ pub struct Config {
   automatic_jsx_runtime: bool,
   jsx_import_source: Option<String>,
   decorators: bool,
+  use_define_for_class_fields: bool,
   is_development: bool,
   react_refresh: bool,
   targets: Option<HashMap<String, String>>,
@@ -234,9 +235,9 @@ pub fn transform(config: Config) -> Result<TransformResult, std::io::Error> {
                   Optional::new(
                     decorators::decorators(decorators::Config {
                       legacy: true,
+                      use_define_for_class_fields: config.use_define_for_class_fields,
                       // Always disabled for now, SWC's implementation doesn't match TSC.
                       emit_metadata: false,
-                      use_define_for_class_fields: true
                     }),
                     config.decorators
                   ),

packages/transformers/js/src/JSTransformer.js

@@ -138,6 +138,8 @@ type TSConfig = {
     jsxImportSource?: string,
     // https://www.typescriptlang.org/tsconfig#experimentalDecorators
     experimentalDecorators?: boolean,
+    // https://www.typescriptlang.org/tsconfig#useDefineForClassFields
+    useDefineForClassFields?: boolean,
     ...
   },
   ...
@@ -152,7 +154,8 @@ export default (new Transformer({
       jsxImportSource,
       automaticJSXRuntime,
       reactRefresh,
-      decorators;
+      decorators,
+      useDefineForClassFields;
     if (config.isSource) {
       let reactLib;
       if (pkg?.alias && pkg.alias['react']) {
@@ -231,6 +234,7 @@ export default (new Transformer({
 
       isJSX = Boolean(compilerOptions?.jsx || pragma);
       decorators = compilerOptions?.experimentalDecorators;
+      useDefineForClassFields = compilerOptions?.useDefineForClassFields;
     }
 
     // Check if we should ignore fs calls
@@ -280,6 +284,7 @@ export default (new Transformer({
       inlineFS,
       reactRefresh,
       decorators,
+      useDefineForClassFields,
     };
   },
   async transform({asset, config, options, logger}) {
@@ -407,6 +412,7 @@ export default (new Transformer({
         !asset.env.isWorklet() &&
         Boolean(config?.reactRefresh),
       decorators: Boolean(config?.decorators),
+      use_define_for_class_fields: Boolean(config?.useDefineForClassFields),
       targets,
       source_maps: !!asset.env.sourceMap,
       scope_hoist: