React Native抽屉导航开发中reanimated初始化及Babel配置错误排查

问题背景 #

开发React Native抽屉导航功能时，安装了@react-navigation/drawer、react-native-gesture-handler和react-native-reanimated库，运行项目时出现连续两个错误：

第一个错误 #

ERROR Error: Failed to initialize react-native-reanimated library, make sure you followed installation steps here: https://docs.swmansion.com/react-native-reanimated/docs/fundamentals/installation/

1. 确保babel.config.js中已配置reanimated的Babel插件（需包含'react-native-reanimated/plugin'）
2. 更新配置后重置构建缓存，执行：yarn start --reset-cache，JS引擎：hermes

按照提示在babel.config.js中添加Plugins:['react-native-reanimated/plugin']，并执行npm start --reset-cache后，出现第二个错误：

第二个错误 #

error: index.js: Unknown option: .Plugins. Check out https://babeljs.io/docs/en/babel-core/#options for more information about options.

相关配置文件 #

package.json #

{
  "name": "Train",
  "version": "0.0.1",
  "private": true,
  "scripts": {
    "android": "react-native run-android",
    "ios": "react-native run-ios",
    "start": "react-native start",
    "test": "jest",
    "lint": "eslint ."
  },
  "dependencies": {
    "@react-native-community/masked-view": "^0.1.11",
    "@react-navigation/drawer": "^6.5.0",
    "@react-navigation/native": "^6.0.13",
    "@react-navigation/stack": "^6.3.1",
    "react": "18.1.0",
    "react-native": "0.70.1",
    "react-native-gesture-handler": "^2.6.2",
    "react-native-reanimated": "^2.10.0",
    "react-native-safe-area-context": "^4.3.4",
    "react-native-screens": "^3.17.0",
    "react-navigation-stack": "^2.10.4"
  },
  "devDependencies": {
    "@babel/core": "^7.12.9",
    "@babel/runtime": "^7.12.5",
    "@react-native-community/eslint-config": "^2.0.0",
    "babel-jest": "^26.6.3",
    "eslint": "^7.32.0",
    "jest": "^26.6.3",
    "metro-react-native-babel-preset": "^0.72.1",
    "react-test-renderer": "18.1.0"
  },
  "jest": {
    "preset": "react-native"
  }
}

index.js #

import {AppRegistry} from 'react-native';
import App from './App';
import Login from './pages/Login';
import Home from './pages/Home';
import cart from './pages/Drawer/cart';
import items from './pages/Drawer/items';
import {name as appName} from './app.json';

AppRegistry.registerComponent(appName, () => App);

babel.config.js #

module.exports = {
  presets: ['module:metro-react-native-babel-preset'],
  Plugins:['react-native-reanimated/plugin'],//I added this line because of the 1st error 
};

App.js #

import React from 'react';
import { NavigationContainer } from '@react-navigation/native';
import { createStackNavigator} from '@react-navigation/stack';
import {createDrawerNavigator} from '@react-navigation/drawer';

//for stack
import Login from './pages/Login';
import Home from './pages/Home';
//for drawer
import cart from './pages/Drawer/cart';
import items from './pages/Drawer/items';
import wallet from './pages/Drawer/wallet';
import orders from './pages/Drawer/orders';


const stack = createStackNavigator();
const Drawer = createDrawerNavigator();

function MystackNav(){
  return(
    <stack.Navigator>
      <stack.Screen name='Login' component={Login} options={{headerShown:false}}/>
      <stack.Screen name='Home' component={Home} options={{headerShown:false}}/>
      <stack.Screen name='Drawer' component={MyDrawer}/>
    </stack.Navigator>
  )
}

function MyDrawer(){
  return(
    <Drawer.Navigator>
      <Drawer.Screen name='cart' component={cart}/>
    </Drawer.Navigator>
  )
}

export default function App(){
  return(
    <NavigationContainer>
      <MystackNav/>
    </NavigationContainer>
  )
}

解决方案 #

第二个错误的核心原因是Babel配置字段名大小写错误：你写的是大写开头的Plugins，而Babel要求的是小写开头的plugins。

步骤1：修正babel.config.js #

修改配置文件，将Plugins改为plugins，并确保react-native-reanimated/plugin放在插件数组的最后一项（Reanimated插件要求必须处于末尾）：

module.exports = {
  presets: ['module:metro-react-native-babel-preset'],
  plugins: ['react-native-reanimated/plugin'], // 注意这里是小写的plugins
};

步骤2：重置缓存并重新构建 #

1. 执行缓存重置命令：

npm start --reset-cache
# 若使用yarn则执行：yarn start --reset-cache

2. 重新运行项目：

# Android
npm run android
# iOS
npm run ios

额外优化建议 #

为保证抽屉导航正常工作，需在index.js最顶部添加react-native-gesture-handler的导入：

import 'react-native-gesture-handler';
import {AppRegistry} from 'react-native';
// 其余代码不变...

内容的提问来源于stack exchange，提问作者Abhiram