From 9b0044e21387f10b005b58fb50c2ea4fcf2f228f Mon Sep 17 00:00:00 2001
From: Lauren Tan <poteto@users.noreply.github.com>
Date: Sat, 11 May 2024 00:19:59 -0400
Subject: [PATCH] Better detection for reanimated

We found this issue through enabling the compiler on the React Conf app.

`babel-preset-expo` automatically adds the `react-native-animated`
plugin to apps that use the preset. This means that Expo apps sometimes
omit the react-native-animated plugin from their config, which was
failing our existing check. This PR copies the same detection that Expo
does for adding reanimated as a fallback

ghstack-source-id: 46f7aec0bc3035a92369f65b0842bafab0089a9e
Pull Request resolved: https://github.com/facebook/react-forget/pull/2953
---
 .../src/Entrypoint/Reanimated.ts              | 27 ++++++++++++++++---
 1 file changed, 23 insertions(+), 4 deletions(-)

diff --git a/compiler/packages/babel-plugin-react-compiler/src/Entrypoint/Reanimated.ts b/compiler/packages/babel-plugin-react-compiler/src/Entrypoint/Reanimated.ts
index 9cf6e51dcb..92775fff00 100644
--- a/compiler/packages/babel-plugin-react-compiler/src/Entrypoint/Reanimated.ts
+++ b/compiler/packages/babel-plugin-react-compiler/src/Entrypoint/Reanimated.ts
@@ -2,10 +2,30 @@ import type * as BabelCore from "@babel/core";
 import { hasOwnProperty } from "../Utils/utils";
 import { PluginOptions } from "./Options";
 
+function hasModule(name: string): boolean {
+  try {
+    return !!require.resolve(name);
+  } catch (error: any) {
+    if (
+      error.code === "MODULE_NOT_FOUND" &&
+      error.message.indexOf(name) !== -1
+    ) {
+      return false;
+    }
+    throw error;
+  }
+}
+
+/**
+ * Tries to detect if reanimated is installed by first looking for the presence of the babel plugin.
+ * However, babel-preset-expo includes it by default so it is occasionally ommitted. If so, we do
+ * a check to see if `react-native-animated` is requireable.
+ *
+ * See https://github.com/expo/expo/blob/e4b8d86442482c7316365a6b7ec1141eec73409d/packages/babel-preset-expo/src/index.ts#L300-L301
+ */
 export function pipelineUsesReanimatedPlugin(
   plugins: Array<BabelCore.PluginItem> | null | undefined
 ): boolean {
-  let hasReanimated = false;
   if (Array.isArray(plugins)) {
     for (const plugin of plugins) {
       if (hasOwnProperty(plugin, "key")) {
@@ -14,13 +34,12 @@ export function pipelineUsesReanimatedPlugin(
           typeof key === "string" &&
           key.indexOf("react-native-reanimated") !== -1
         ) {
-          hasReanimated = true;
-          break;
+          return true;
         }
       }
     }
   }
-  return hasReanimated;
+  return hasModule("react-native-reanimated");
 }
 
 export function injectReanimatedFlag(options: PluginOptions): PluginOptions {