Pass correct useDefineForClassFields, derived from tsconfig

TypeStrong · Sep 14, 2023 · 487fe92 · 487fe92
1 parent a045c4e
commit 487fe92
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diff --git a/src/test/transpilers.spec.ts b/src/test/transpilers.spec.ts
@@ -139,4 +139,117 @@ test.suite('swc', (test) => {
       `
     );
   });
+
+  test.suite('useDefineForClassFields', (test) => {
+    const input = outdent`
+      class Foo {
+        bar = 1;
+      }
+    `;
+    const outputNative = outdent`
+      let Foo = class Foo {
+          bar = 1;
+      };
+    `;
+    const outputCtorAssignment = outdent`
+      let Foo = class Foo {
+          constructor(){
+              this.bar = 1;
+          }
+      };
+    `;
+    const outputDefine = outdent`
+      function _define_property(obj, key, value) {
+          if (key in obj) {
+              Object.defineProperty(obj, key, {
+                  value: value,
+                  enumerable: true,
+                  configurable: true,
+                  writable: true
+              });
+          } else {
+              obj[key] = value;
+          }
+          return obj;
+      }
+      let Foo = class Foo {
+          constructor(){
+              _define_property(this, "bar", 1);
+          }
+      };
+    `;
+    test(
+      'useDefineForClassFields unset, should default to true and emit native property assignment b/c `next` target',
+      compileMacro,
+      {
+        target: 'ESNext',
+      },
+      input,
+      outputNative
+    );
+    test(
+      'useDefineForClassFields unset, should default to true and emit native property assignment b/c new target',
+      compileMacro,
+      {
+        target: 'ES2022',
+      },
+      input,
+      outputNative
+    );
+    test(
+      'useDefineForClassFields unset, should default to false b/c old target',
+      compileMacro,
+      {
+        target: 'ES2021',
+      },
+      input,
+      outputCtorAssignment
+    );
+    test(
+      'useDefineForClassFields unset, should default to false b/c no target',
+      compileMacro,
+      {},
+      input,
+      outputCtorAssignment
+    );
+    test(
+      'useDefineForClassFields=true, should emit native property assignment b/c new target',
+      compileMacro,
+      {
+        useDefineForClassFields: true,
+        target: 'ES2022',
+      },
+      input,
+      outputNative
+    );
+    test(
+      'useDefineForClassFields=true, should emit define b/c old target',
+      compileMacro,
+      {
+        useDefineForClassFields: true,
+        target: 'ES2021',
+      },
+      input,
+      outputDefine
+    );
+    test(
+      'useDefineForClassFields=false, new target, should still emit legacy property assignment in ctor',
+      compileMacro,
+      {
+        useDefineForClassFields: false,
+        target: 'ES2022',
+      },
+      input,
+      outputCtorAssignment
+    );
+    test(
+      'useDefineForClassFields=false, old target, should emit legacy property assignment in ctor',
+      compileMacro,
+      {
+        useDefineForClassFields: false,
+      },
+      input,
+      outputCtorAssignment
+    );
+  });
 });
diff --git a/src/transpilers/swc.ts b/src/transpilers/swc.ts
@@ -3,6 +3,7 @@ import type * as swcWasm from '@swc/wasm';
 import type * as swcTypes from '@swc/core';
 import type { CreateTranspilerOptions, Transpiler } from './types';
 import type { NodeModuleEmitKind } from '..';
+import { getUseDefineForClassFields } from '../ts-internals';
 
 type SwcInstance = typeof swcTypes;
 export interface SwcTranspilerOptions extends CreateTranspilerOptions {
@@ -194,6 +195,8 @@ export function createSwcOptions(
     jsx === JsxEmit.ReactJSX || jsx === JsxEmit.ReactJSXDev ? 'automatic' : undefined;
   const jsxDevelopment: swcTypes.ReactConfig['development'] = jsx === JsxEmit.ReactJSXDev ? true : undefined;
 
+  const useDefineForClassFields = getUseDefineForClassFields(compilerOptions);
+
   const nonTsxOptions = createVariant(false);
   const tsxOptions = createVariant(true);
   return { nonTsxOptions, tsxOptions };
@@ -233,6 +236,7 @@ export function createSwcOptions(
             pragmaFrag: jsxFragmentFactory!,
             runtime: jsxRuntime,
           },
+          useDefineForClassFields,
         },
         keepClassNames,
         experimental: {

diff --git a/src/ts-internals.ts b/src/ts-internals.ts
@@ -329,3 +329,28 @@ function replaceWildcardCharacter(match: string, singleAsteriskRegexFragment: st
 function isImplicitGlob(lastPathComponent: string): boolean {
   return !/[.*?]/.test(lastPathComponent);
 }
+
+const ts_ScriptTarget_ES5 = 1;
+const ts_ScriptTarget_ES2022 = 9;
+const ts_ScriptTarget_ESNext = 99;
+const ts_ModuleKind_Node16 = 100;
+const ts_ModuleKind_NodeNext = 199;
+// https://github.com/microsoft/TypeScript/blob/fc418a2e611c88cf9afa0115ff73490b2397d311/src/compiler/utilities.ts#L8761
+export function getUseDefineForClassFields(compilerOptions: _ts.CompilerOptions): boolean {
+  return compilerOptions.useDefineForClassFields === undefined
+    ? getEmitScriptTarget(compilerOptions) >= ts_ScriptTarget_ES2022
+    : compilerOptions.useDefineForClassFields;
+}
+
+// https://github.com/microsoft/TypeScript/blob/fc418a2e611c88cf9afa0115ff73490b2397d311/src/compiler/utilities.ts#L8556
+export function getEmitScriptTarget(compilerOptions: {
+  module?: _ts.CompilerOptions['module'];
+  target?: _ts.CompilerOptions['target'];
+}): _ts.ScriptTarget {
+  return (
+    compilerOptions.target ??
+    ((compilerOptions.module === ts_ModuleKind_Node16 && ts_ScriptTarget_ES2022) ||
+      (compilerOptions.module === ts_ModuleKind_NodeNext && ts_ScriptTarget_ESNext) ||
+      ts_ScriptTarget_ES5)
+  );
+}