[corejs3] Inject esnext.symbol.metadata for decorated classes (#179)

Co-authored-by: liuxingbaoyu <[email protected]>

packages/babel-plugin-polyfill-corejs3/package.json

@@ -32,10 +32,12 @@
   "devDependencies": {
     "@babel/core": "^7.22.6",
     "@babel/helper-plugin-test-runner": "^7.22.5",
+    "@babel/plugin-proposal-decorators": "^7.22.15",
     "@babel/plugin-transform-class-properties": "^7.22.5",
     "@babel/plugin-transform-classes": "^7.22.6",
     "@babel/plugin-transform-for-of": "^7.22.5",
     "@babel/plugin-transform-modules-commonjs": "^7.22.5",
+    "@babel/plugin-transform-runtime": "^7.22.15",
     "@babel/plugin-transform-spread": "^7.22.5",
     "core-js": "^3.32.0",
     "core-js-pure": "^3.32.0"

packages/babel-plugin-polyfill-corejs3/src/built-in-definitions.ts

@@ -204,6 +204,11 @@ const IteratorDependencies = [
   "es.object.to-string",
 ];
 
+export const DecoratorMetadataDependencies = [
+  "esnext.symbol.metadata",
+  "esnext.function.metadata",
+];
+
 const TypedArrayStaticMethods = {
   from: define(null, ["es.typed-array.from"]),
   fromAsync: define(null, [
@@ -640,10 +645,7 @@ export const StaticProperties: ObjectMap2<CoreJSPolyfillDescriptor> = {
       "es.symbol.match-all",
       "es.string.match-all",
     ]),
-    metadata: define("symbol/metadata", [
-      "esnext.symbol.metadata",
-      "esnext.function.metadata",
-    ]),
+    metadata: define("symbol/metadata", DecoratorMetadataDependencies),
     metadataKey: define("symbol/metadata-key", ["esnext.symbol.metadata-key"]),
     observable: define("symbol/observable", ["esnext.symbol.observable"]),
     patternMatch: define("symbol/pattern-match", [

packages/babel-plugin-polyfill-corejs3/src/index.ts

@@ -8,6 +8,7 @@ import {
   PromiseDependenciesWithIterators,
   StaticProperties,
   InstanceProperties,
+  DecoratorMetadataDependencies,
   type CoreJSPolyfillDescriptor,
 } from "./built-in-definitions";
 import canSkipPolyfill from "./usage-filters";
@@ -375,6 +376,18 @@ export default defineProvider<Options>(function (
           maybeInjectGlobal(CommonIterators, getUtils(path));
         }
       },
+
+      // Decorators metadata
+      Class(path: NodePath<t.Class>) {
+        const hasDecorators =
+          path.node.decorators?.length ||
+          path.node.body.body.some(
+            el => (el as t.ClassMethod).decorators?.length,
+          );
+        if (hasDecorators) {
+          maybeInjectGlobal(DecoratorMetadataDependencies, getUtils(path));
+        }
+      },
     },
   };
 });

packages/babel-plugin-polyfill-corejs3/test/fixtures/usage-global/decorators/input.js

@@ -0,0 +1,3 @@
+class A {
+  @dec foo = 2;
+}

packages/babel-plugin-polyfill-corejs3/test/fixtures/usage-global/decorators/options.json

@@ -0,0 +1,7 @@
+{
+  "plugins": [
+    ["@@/polyfill-corejs3", { "method": "usage-global", "version": "3.31.0", "proposals": true }],
+    ["@babel/plugin-proposal-decorators", { "version": "2023-05" }],
+    ["@babel/plugin-transform-runtime", { "version": "7.100.0" }]
+  ]
+}

packages/babel-plugin-polyfill-corejs3/test/fixtures/usage-global/decorators/output.js

@@ -0,0 +1,14 @@
+var _applyDecs = require("@babel/runtime-corejs3/helpers/applyDecs2305").default;
+var _dec, _init_foo;
+require("core-js/modules/esnext.function.metadata.js");
+require("core-js/modules/esnext.symbol.metadata.js");
+require("core-js/modules/es.string.iterator.js");
+require("core-js/modules/es.array.iterator.js");
+require("core-js/modules/web.dom-collections.iterator.js");
+_dec = dec;
+class A {
+  static {
+    [_init_foo] = _applyDecs(this, [[_dec, 0, "foo"]], []).e;
+  }
+  foo = _init_foo(this, 2);
+}