fix(esbuild): use useDefineForClassFields: false when no compilerOptions.target is declared (#13708)

Author: sapphi-red

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

@@ -378,6 +378,11 @@ describe('transformWithEsbuild', () => {
       })
       expect(actual).toBe(defineForClassFieldsTrueTransformedCode)
     })
+
+    test('target: es2022 and tsconfig.target: undefined => false', async () => {
+      const actual = await transformClassCode('es2022', {})
+      expect(actual).toBe(defineForClassFieldsFalseTransformedCode)
+    })
   })
 })
 

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

@@ -132,6 +132,16 @@ export async function transformWithEsbuild(
       ...tsconfigRaw?.compilerOptions,
     }
 
+    // esbuild uses `useDefineForClassFields: true` when `tsconfig.compilerOptions.target` isn't declared
+    // but we want `useDefineForClassFields: false` when `tsconfig.compilerOptions.target` isn't declared
+    // to align with the TypeScript's behavior
+    if (
+      compilerOptions.useDefineForClassFields === undefined &&
+      compilerOptions.target === undefined
+    ) {
+      compilerOptions.useDefineForClassFields = false
+    }
+
     // esbuild uses tsconfig fields when both the normal options and tsconfig was set
     // but we want to prioritize the normal options
     if (options) {