Generate helper metadata at build time (#16501)

babel.config.js

@@ -498,6 +498,16 @@ function pluginPolyfillsOldNode({ template, types: t }) {
       // https://github.com/nodejs/node/blob/main/doc/changelogs/CHANGELOG_V16.md#v8-93
       replacement: template`hasOwnProperty.call`,
     },
+    {
+      name: "Object.entries",
+      necessary({ parent, node }) {
+        // To avoid infinite replacement loops
+        return !t.isLogicalExpression(parent, { operator: "||", left: node });
+      },
+      supported: path =>
+        path.parentPath.isCallExpression({ callee: path.node }),
+      replacement: template`Object.entries || (o => Object.keys(o).map(k => [k, o[k]]))`,
+    },
     {
       name: "fs.rmSync",
       necessary({ node, parent }) {
@@ -543,7 +553,8 @@ function pluginPolyfillsOldNode({ template, types: t }) {
           if (!polyfill.necessary(path)) return;
           if (!polyfill.supported(path)) {
             throw path.buildCodeFrameError(
-              `This '${polyfill.name}' usage is not supported by the inline polyfill.`
+              `This '${polyfill.name}' usage is not supported by the inline polyfill.\n` +
+                path.parentPath.toString()
             );
           }
 

packages/babel-core/src/tools/build-external-helpers.ts

@@ -23,7 +23,6 @@ import {
   variableDeclarator,
 } from "@babel/types";
 import type * as t from "@babel/types";
-import File from "../transformation/file/file.ts";
 import type { Replacements } from "@babel/template";
 
 // Wrapped to avoid wasting time parsing this when almost no-one uses
@@ -174,8 +173,24 @@ function buildHelpers(
 
     const ref = (refs[name] = getHelperReference(name));
 
-    helpers.ensure(name, File);
-    const { nodes } = helpers.get(name, getHelperReference, ref);
+    const { nodes } = helpers.get(
+      name,
+      getHelperReference,
+      namespace ? null : `_${name}`,
+      [],
+      namespace
+        ? (ast, exportName, mapExportBindingAssignments) => {
+            mapExportBindingAssignments(node =>
+              assignmentExpression("=", ref, node),
+            );
+            ast.body.push(
+              expressionStatement(
+                assignmentExpression("=", ref, identifier(exportName)),
+              ),
+            );
+          }
+        : null,
+    );
 
     body.push(...nodes);
   });

packages/babel-core/src/transformation/file/file.ts

@@ -163,7 +163,7 @@ export default class File {
     }
 
     // make sure that the helper exists
-    helpers.ensure(name, File);
+    helpers.minVersion(name);
 
     const uid = (this.declarations[name] =
       this.scope.generateUidIdentifier(name));
@@ -176,7 +176,7 @@ export default class File {
     const { nodes, globals } = helpers.get(
       name,
       dep => dependencies[dep],
-      uid,
+      uid.name,
       Object.keys(this.scope.getAllBindings()),
     );
 

packages/babel-core/test/api.js

@@ -840,24 +840,6 @@ describe("api", function () {
   });
 
   describe("buildExternalHelpers", function () {
-    describe("smoke tests", function () {
-      it("builds external helpers in global output type", function () {
-        babel.buildExternalHelpers(null, "global");
-      });
-
-      it("builds external helpers in module output type", function () {
-        babel.buildExternalHelpers(null, "module");
-      });
-
-      it("builds external helpers in umd output type", function () {
-        babel.buildExternalHelpers(null, "umd");
-      });
-
-      it("builds external helpers in var output type", function () {
-        babel.buildExternalHelpers(null, "var");
-      });
-    });
-
     it("all", function () {
       const script = babel.buildExternalHelpers();
       expect(script).toEqual(expect.stringContaining("classCallCheck"));
@@ -880,6 +862,88 @@ describe("api", function () {
       const script = babel.buildExternalHelpers(["typeof"]);
       expect(script).toEqual(expect.stringContaining("typeof"));
     });
+
+    describe("output types", function () {
+      it("global", function () {
+        const script = babel.buildExternalHelpers(["get"], "global");
+        expect(script).toMatchInlineSnapshot(`
+          "(function (global) {
+            var babelHelpers = global.babelHelpers = {};
+            function _get() {
+              return babelHelpers.get = _get = \\"undefined\\" != typeof Reflect && Reflect.get ? Reflect.get.bind() : function (e, t, r) {
+                var p = babelHelpers.superPropBase(e, t);
+                if (p) {
+                  var n = Object.getOwnPropertyDescriptor(p, t);
+                  return n.get ? n.get.call(arguments.length < 3 ? e : r) : n.value;
+                }
+              }, _get.apply(null, arguments);
+            }
+            babelHelpers.get = _get;
+          })(typeof global === \\"undefined\\" ? self : global);"
+        `);
+      });
+
+      it("umd", function () {
+        const script = babel.buildExternalHelpers(["get"], "umd");
+        expect(script).toMatchInlineSnapshot(`
+          "(function (root, factory) {
+            if (typeof define === \\"function\\" && define.amd) {
+              define([\\"exports\\"], factory);
+            } else if (typeof exports === \\"object\\") {
+              factory(exports);
+            } else {
+              factory(root.babelHelpers = {});
+            }
+          })(this, function (global) {
+            var babelHelpers = global;
+            function _get() {
+              return babelHelpers.get = _get = \\"undefined\\" != typeof Reflect && Reflect.get ? Reflect.get.bind() : function (e, t, r) {
+                var p = babelHelpers.superPropBase(e, t);
+                if (p) {
+                  var n = Object.getOwnPropertyDescriptor(p, t);
+                  return n.get ? n.get.call(arguments.length < 3 ? e : r) : n.value;
+                }
+              }, _get.apply(null, arguments);
+            }
+            babelHelpers.get = _get;
+          });"
+        `);
+      });
+
+      it("var", function () {
+        const script = babel.buildExternalHelpers(["get"], "var");
+        expect(script).toMatchInlineSnapshot(`
+          "var babelHelpers = {};
+          function _get() {
+            return babelHelpers.get = _get = \\"undefined\\" != typeof Reflect && Reflect.get ? Reflect.get.bind() : function (e, t, r) {
+              var p = babelHelpers.superPropBase(e, t);
+              if (p) {
+                var n = Object.getOwnPropertyDescriptor(p, t);
+                return n.get ? n.get.call(arguments.length < 3 ? e : r) : n.value;
+              }
+            }, _get.apply(null, arguments);
+          }
+          babelHelpers.get = _get;
+          babelHelpers;"
+        `);
+      });
+
+      it("module", function () {
+        const script = babel.buildExternalHelpers(["get"], "module");
+        expect(script).toMatchInlineSnapshot(`
+          "export { _get as get };
+          function _get() {
+            return _get = \\"undefined\\" != typeof Reflect && Reflect.get ? Reflect.get.bind() : function (e, t, r) {
+              var p = _superPropBase(e, t);
+              if (p) {
+                var n = Object.getOwnPropertyDescriptor(p, t);
+                return n.get ? n.get.call(arguments.length < 3 ? e : r) : n.value;
+              }
+            }, _get.apply(null, arguments);
+          }"
+        `);
+      });
+    });
   });
 
   describe("handle parsing errors", function () {

packages/babel-helpers/package.json

@@ -16,11 +16,9 @@
   "main": "./lib/index.js",
   "dependencies": {
     "@babel/template": "workspace:^",
-    "@babel/traverse": "workspace:^",
     "@babel/types": "workspace:^"
   },
   "devDependencies": {
-    "@babel/core": "workspace:^",
     "@babel/generator": "workspace:^",
     "@babel/helper-plugin-test-runner": "workspace:^",
     "@babel/parser": "workspace:^",