[babel 8] Move @babel/register transform to a separate worker (#14025)

packages/babel-register/src/nodeWrapper.js

@@ -0,0 +1,29 @@
+/**
+ * This file wraps the implementation of register so all modules `require()`-ed
+ * internally within register are stored in a separate module cache.
+ * This prevents un-transformed modules being stored in global module cache,
+ * and allows register to transform these modules if they are loaded externally.
+ */
+
+// TODO: Remove this file in Babel 8
+
+const Module = require("module");
+
+const globalModuleCache = Module._cache;
+const internalModuleCache = Object.create(null);
+
+Module._cache = internalModuleCache;
+const node = require("./node");
+
+// NOTE: This Module._cache set is intercepted by the beforeEach hook in
+// packages/babel-register/test/index.js to install dependencies mocks.
+Module._cache = globalModuleCache;
+
+// Add source-map-support to global cache as it's stateful
+const smsPath = require.resolve("source-map-support");
+globalModuleCache[smsPath] = internalModuleCache[smsPath];
+
+const register = node.default;
+register();
+
+module.exports = node;