Enable shipped proposals in Babel (#17909)

build-scripts/bundle.cjs

@@ -100,6 +100,7 @@ module.exports.babelOptions = ({ latestBuild, isProdBuild, isTestBuild }) => ({
         useBuiltIns: latestBuild ? false : "entry",
         corejs: latestBuild ? false : { version: "3.32", proposals: true },
         bugfixes: true,
+        shippedProposals: true,
       },
     ],
     "@babel/preset-typescript",

build-scripts/list-plugins-and-polyfills.js

@@ -6,6 +6,8 @@ import presetEnv from "@babel/preset-env";
 import compilationTargets from "@babel/helper-compilation-targets";
 import coreJSCompat from "core-js-compat";
 import { logPlugin } from "@babel/preset-env/lib/debug.js";
+// eslint-disable-next-line import/no-relative-packages
+import shippedPolyfills from "../node_modules/babel-plugin-polyfill-corejs3/lib/shipped-proposals.js";
 import { babelOptions } from "./bundle.cjs";
 
 const detailsOpen = (heading) =>
@@ -26,6 +28,22 @@ const dummyAPI = {
   targets: () => ({}),
 };
 
+// Generate filter function based on proposal/method inputs
+// Copied and adapted from babel-plugin-polyfill-corejs3/esm/index.mjs
+const polyfillFilter = (method, proposals, shippedProposals) => (name) => {
+  if (proposals || method === "entry-global") return true;
+  if (shippedProposals && shippedPolyfills.default.has(name)) {
+    return true;
+  }
+  if (name.startsWith("esnext.")) {
+    const esName = `es.${name.slice(7)}`;
+    // If its imaginative esName is not in latest compat data, it means the proposal is not stage 4
+    return esName in coreJSCompat.data;
+  }
+  return true;
+};
+
+// Log the plugins and polyfills for each build environment
 for (const buildType of ["Modern", "Legacy"]) {
   const browserslistEnv = buildType.toLowerCase();
   const babelOpts = babelOptions({ latestBuild: browserslistEnv === "modern" });
@@ -46,7 +64,13 @@ for (const buildType of ["Modern", "Legacy"]) {
     const targets = compilationTargets.default(babelOpts?.targets, {
       browserslistEnv,
     });
-    const polyfillList = coreJSCompat({ targets }).list;
+    const polyfillList = coreJSCompat({ targets }).list.filter(
+      polyfillFilter(
+        `${presetEnvOpts.useBuiltIns}-global`,
+        presetEnvOpts?.corejs?.proposals,
+        presetEnvOpts?.shippedProposals
+      )
+    );
     console.log(
       "The following %i polyfills may be injected by Babel:\n",
       polyfillList.length