From 870b98222ea8f0f2a049de0a775956726fdc797a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Nicol=C3=B2=20Ribaudo?= <nicolo.ribaudo@gmail.com>
Date: Thu, 3 Jun 2021 22:06:59 +0200
Subject: [PATCH] Expose CJS proxy in `@babel/core`

---
 packages/babel-core/package.json |  4 ++++
 packages/babel-core/proxy.cjs    | 25 +++++++++++++++++++++++++
 2 files changed, 29 insertions(+)
 create mode 100644 packages/babel-core/proxy.cjs

diff --git a/packages/babel-core/package.json b/packages/babel-core/package.json
index adba85eb958a..2e4dbdde0a5b 100644
--- a/packages/babel-core/package.json
+++ b/packages/babel-core/package.json
@@ -4,6 +4,10 @@
   "description": "Babel compiler core.",
   "type": "module",
   "main": "./lib/index.js",
+  "exports": {
+    "require": "./proxy.cjs",
+    "default": "./lib/index.js"
+  },
   "author": "The Babel Team (https://babel.dev/team)",
   "license": "MIT",
   "publishConfig": {
diff --git a/packages/babel-core/proxy.cjs b/packages/babel-core/proxy.cjs
new file mode 100644
index 000000000000..799f00777c17
--- /dev/null
+++ b/packages/babel-core/proxy.cjs
@@ -0,0 +1,25 @@
+"use strict";
+
+const babelP = import("./lib/index.js");
+
+proxy("createConfigItem");
+proxy("loadPartialConfig");
+proxy("loadOptions");
+proxy("transform");
+proxy("transformFile");
+proxy("transformFromAst");
+proxy("parse");
+
+function proxy(name) {
+  exports[`${name}Sync`] = () => {
+    throw new Error(
+      "Only async methods are supported when using `require()` to load `@babel/core`."
+    );
+  };
+  exports[`${name}Async`] = (...args) =>
+    babelP.then(babel => babel[`${name}Async`](...args));
+  exports[name] = (...args) => {
+    const cb = args.pop();
+    babelP.then(babel => babel[name](...args, cb), cb);
+  };
+}