feat: enable decorator-metadata transform automatically (#315)

Author: sapphi-red

packages/vite/src/node/__tests__/plugins/fixtures/oxc-tsconfigs/decorator-metadata/tsconfig.json

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

packages/vite/src/node/__tests__/plugins/oxc.spec.ts

@@ -156,6 +156,28 @@ describe('transformWithOxc', () => {
       expect(actual).toBe(defineForClassFieldsFalseTransformedCode)
     })
   })
+
+  test('supports emitDecoratorMetadata: true', async () => {
+    const result = await transformWithOxc(
+      `
+          function LogMethod(target: any, propertyKey: string | symbol, descriptor: PropertyDescriptor) {
+            console.log(target, propertyKey, descriptor);
+          }
+
+          class Demo {
+            @LogMethod
+            public foo(bar: number) {}
+          }
+
+          const demo = new Demo();
+        `,
+      path.resolve(
+        import.meta.dirname,
+        './fixtures/oxc-tsconfigs/decorator-metadata/bar.ts',
+      ),
+    )
+    expect(result?.code).toContain('_decorateMetadata("design:type"')
+  })
 })
 
 describe('renderChunk', () => {

packages/vite/src/node/plugins/esbuild.ts

@@ -69,6 +69,7 @@ type TSConfigJSON = {
     preserveValueImports?: boolean
     target?: string
     useDefineForClassFields?: boolean
+    emitDecoratorMetadata?: boolean
     verbatimModuleSyntax?: boolean
   }
   [key: string]: any

packages/vite/src/node/plugins/oxc.ts

@@ -148,6 +148,13 @@ export async function transformWithOxc(
           resolvedOptions.decorator ??= {}
           resolvedOptions.decorator.legacy = experimentalDecorators
         }
+        const emitDecoratorMetadata =
+          loadedCompilerOptions.emitDecoratorMetadata
+        if (emitDecoratorMetadata !== undefined) {
+          resolvedOptions.decorator ??= {}
+          resolvedOptions.decorator.emitDecoratorMetadata =
+            emitDecoratorMetadata
+        }
       }
 
       /**