将react native web添加到现有react native应用程序时出错

Question

通过执行react native init react nativeweb，我创建了一个react native应用程序。

然后，我按照这里的说明，向它添加react-nate-web。

我还添加了一个索引。网状物js我的应用程序根文件夹下的文件。以下是该文件的外观：

import React, { Component } from "react";
import { AppRegistry, StyleSheet, Text, View } from "react-native";

class ReactNativeWeb extends Component {
  render() {
    return (
      <View style={styles.container}>
        <Text style={styles.welcome}>Welcome to React Native!</Text>
        <Text style={styles.instructions}>
          To get started, edit index.web.js
        </Text>
        <Text style={styles.instructions}>Press Cmd+R to reload</Text>
      </View>
    );
  }
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    justifyContent: "center",
    alignItems: "center",
    backgroundColor: "#F5FCFF"
  },
  welcome: {
    fontSize: 20,
    textAlign: "center",
    margin: 10
  },
  instructions: {
    textAlign: "center",
    color: "#333333",
    marginBottom: 5
  }
});

AppRegistry.registerComponent("ReactNativeWeb", () => ReactNativeWeb);
AppRegistry.runApplication("ReactNativeWeb", {
  rootTag: document.getElementById("react-app")
});

这是我的webpack.config.js文件：

const path = require("path");
const webpack = require("webpack");

const appDirectory = path.resolve(__dirname, "../");

// This is needed for webpack to compile JavaScript.
// Many OSS React Native packages are not compiled to ES5 before being
// published. If you depend on uncompiled packages they may cause webpack build
// errors. To fix this webpack can be configured to compile to the necessary
// `node_module`.
const babelLoaderConfiguration = {
  test: /\.js$/,
  // Add every directory that needs to be compiled by Babel during the build.
  include: [
    path.resolve(appDirectory, "index.web.js"),
    path.resolve(appDirectory, "src"),
    path.resolve(appDirectory, "node_modules/react-native-uncompiled")
  ],
  use: {
    loader: "babel-loader",
    options: {
      cacheDirectory: true,
      // The 'react-native' preset is recommended to match React Native's packager
      presets: ["react-native"],
      // Re-write paths to import only the modules needed by the app
      plugins: ["react-native-web"]
    }
  }
};

// This is needed for webpack to import static images in JavaScript files.
const imageLoaderConfiguration = {
  test: /\.(gif|jpe?g|png|svg)$/,
  use: {
    loader: "url-loader",
    options: {
      name: "[name].[ext]"
    }
  }
};

module.exports = {
  entry: [
    // load any web API polyfills
    // path.resolve(appDirectory, 'polyfills-web.js'),
    // your web-specific entry file
    path.resolve(appDirectory, "index.web.js")
  ],

  // configures where the build ends up
  output: {
    filename: "bundle.web.js",
    path: path.resolve(appDirectory, "dist")
  },

  // ...the rest of your config

  module: {
    rules: [babelLoaderConfiguration, imageLoaderConfiguration]
  },

  resolve: {
    // This will only alias the exact import "react-native"
    alias: {
      "react-native$": "react-native-web"
    },
    // If you're working on a multi-platform React Native app, web-specific
    // module implementations should be written in files using the extension
    // `.web.js`.
    extensions: [".web.js", ".js"]
  }
};

下面是我在中看到的内容。bablerc文件：

{
  "presets": ["@babel/preset-env"]
}

但是，当我尝试使用下面的命令运行此命令时，我得到以下错误。

./node_modules/.bin/webpack-dev-server -d --config ./web/webpack.con

错误：

错误/指数网状物js模块构建失败（来自./node_modules/babel loader/lib/index.js）：TypeError:无法在作用域读取null的属性“bindings”。在BlockScoping中移动bindings到（/Users/aliyar/ReactNativeWeb/node_modules/@babel/traverse/lib/scope/index.js:867:13）。在BlockScoping中更新copeinfo（/Users/aliyar/ReactNativeWeb/node_modules/babel-plugin-transform-es2015-block-scoping/lib/index.js:364:17）。在PluginPass上运行（/Users/aliyar/reactiveweb/node_modules/babel-plugin-transform-es2015-block-scoping/lib/index.js:330:12）。BlockStatementSwitchStatementProgram（/Users/aliyar/ReactNativeWeb/node_modules/babel-plugin-transform-es2015-block-scoping/lib/index.js:70:24）在newFn（/Users/aliyar/ReactNativeWeb/node_modules/@babel/traverse/lib/visitors.js:193:21）在NodePath_在NodePath调用（/Users/aliyar/ReactNativeWeb/node_modules/@babel/traverse/lib/path/context.js:53:20）。在NodePath调用（/Users/aliyar/ReactNativeWeb/node_modules/@babel/traverse/lib/path/context.js:40:17）。在TraversalContext访问（/Users/aliyar/ReactNativeWeb/node_modules/@babel/traverse/lib/path/context.js:88:12）。在TraversalContext上访问Queue（/Users/aliyar/ReactNativeWeb/node_modules/@babel/traverse/lib/context.js:118:16）。Visitinggle（/Users/aliyar/ReactNativeWeb/node_modules/@babel/traverse/lib/context.js:90:19）@multi（webpack）-开发服务器/客户端？http://localhost:8080（网页包）/hot/dev服务器。js/指数网状物js main[2]

知道我为什么会出错吗？

Answer 1

我能够通过将Babel-preset-react-本地升级到5.0.2版本来解决您的问题。其他一切都应该与您的设置相同。

这是我完整的软件包。json：

{
  "name": "ReactNativeWeb02",
  "version": "0.0.1",
  "private": true,
  "scripts": {
    "start": "node node_modules/react-native/local-cli/cli.js start",
    "test": "jest",
    "build": "./node_modules/.bin/webpack-dev-server -d --config ./web/webpack.config.js --inline --hot --colors"
  },
  "dependencies": {
    "react": "^16.7.0",
    "react-dom": "^16.7.0",
    "react-native": "0.58.0",
    "react-native-web": "^0.10.0-alpha.3"
  },
  "devDependencies": {
    "babel-plugin-react-native-web": "^0.9.13",
    "babel-preset-react-native": "^5.0.2",
    "babel-core": "7.0.0-bridge.0",
    "babel-jest": "23.6.0",
    "babel-loader": "^8.0.5",
    "jest": "23.6.0",
    "metro-react-native-babel-preset": "0.51.1",
    "react-test-renderer": "16.6.3",
    "url-loader": "^1.1.2",
    "webpack": "^4.29.0",
    "webpack-cli": "^3.2.1",
    "webpack-dev-server": "^3.1.14"
  },
  "jest": {
    "preset": "react-native"
  }
}

我希望这有帮助。