perf: avoid loadFullConfig when creating block hoist plugin (#13223)

JLHwung · web-flow · commit 88da2e80ede2 · 2021-04-27T14:39:18.000-04:00
* perf: avoid loadFullConfig when creating block hoist plugin

* address code review comments
diff --git a/packages/babel-core/src/transformation/block-hoist-plugin.ts b/packages/babel-core/src/transformation/block-hoist-plugin.ts
@@ -1,22 +1,18 @@
-import loadConfig from "../config";
-
-import type { Plugin } from "../config";
+import traverse from "@babel/traverse";
+import Plugin from "../config/plugin";
 
 let LOADED_PLUGIN: Plugin | void;
 
 export default function loadBlockHoistPlugin(): Plugin {
   if (!LOADED_PLUGIN) {
-    // Lazy-init the internal plugin to remove the init-time circular
-    // dependency between plugins being passed @babel/core's export object,
-    // which loads this file, and this 'loadConfig' loading plugins.
-    const config = loadConfig.sync({
-      babelrc: false,
-      configFile: false,
-      browserslistConfigFile: false,
-      plugins: [blockHoistPlugin],
-    });
-    LOADED_PLUGIN = config ? config.passes[0][0] : undefined;
-    if (!LOADED_PLUGIN) throw new Error("Assertion failure");
+    // cache the loaded blockHoist plugin plugin
+    LOADED_PLUGIN = new Plugin(
+      {
+        ...blockHoistPlugin,
+        visitor: traverse.explode(blockHoistPlugin.visitor),
+      },
+      {},
+    );
   }
 
   return LOADED_PLUGIN;
