javascript - Webpack + React16 + Javascript ES6 "Unexpected token"错误

Question

我知道这个问题被问了大约一千次，但我没有找到任何有效的解决方案。我仍然遇到同样的错误。这是我的配置文件:

package.json:

{
    "scripts": {
        "start": "webpack-dev-server",
        "build": "webpack"
    },
    "dependencies": {
        "jquery": "^3.2.1",
        "react": "^16.1.1",
        "react-dom": "^16.1.1"
    },
    "devDependencies": {
        "babel": "^6.23.0",
        "babel-cli": "^6.26.0",
        "babel-core": "^6.26.0",
        "babel-loader": "^7.1.2",
        "babel-preset-es2015": "^6.24.1",
        "babel-preset-react": "^6.24.1",
        "babel-preset-stage-0": "^6.24.1",
        "clean-webpack-plugin": "^0.1.17",
        "css-loader": "^0.28.7",
        "html-webpack-plugin": "^2.30.1",
        "style-loader": "^0.19.0",
        "webpack": "^3.8.1",
        "webpack-dev-server": "^2.9.4"
    }
}

webpack.config.js:

const path = require('path');
const webpack = require('webpack');
const HtmlWebpackPlugin = require('html-webpack-plugin');
const CleanWebpackPlugin = require('clean-webpack-plugin');

module.exports = {
    entry: './src/app/app.jsx',
    devtool: 'source-map',
    devServer: {
        contentBase: path.join(__dirname, "dist"),
        hot: true
    },
    module: {
        rules: [
            {
                test: /\.css$/,
                use: [
                    'style-loader',
                    'css-loader'
                ]
            }
        ],
        loaders: [
            {
                test: /\.jsx?$/,
                exclude: /node_modules/,
                loader: "babel-loader",
                query:
                    {
                        presets: ['es2015', 'react']
                    }
            }
        ]
    },
    plugins: [
        new HtmlWebpackPlugin({
            template: './src/app/index.html'
        }),
        new webpack.NamedModulesPlugin(),
        new webpack.HotModuleReplacementPlugin()
    ],
    output: {
        path: path.resolve(__dirname, 'dist'),
        filename: 'app.bundle.js'
    }
};

应用程序.jsx:

import React from "react"

React.render(<h1>hello world</h1>, document.getElementById("root-component"));

Webpack 抛出以下错误:

ERROR in ./src/app/app.jsx
Module parse failed: Unexpected token (3:13)
You may need an appropriate loader to handle this file type.
| import React from "react"
|
| React.render(<h1>hello world</h1>, document.getElementById("root-component"));

我尝试了多种解决方案(比如添加带有预设的 .babelrc 文件)，但没有任何效果。有帮助吗？

Answer 1

根据 webpack v3，您的 webpack.config.js 不正确。

您需要在 rules 数组中添加另一个条目，就像加载 CSS 一样。
此外，query 应重命名为 options。

参见 Webpack Documentation有关从 v2 迁移到 v3 的更多信息

固定的webpack.config.js如下:

const path = require('path');
const webpack = require('webpack');
const HtmlWebpackPlugin = require('html-webpack-plugin');
const CleanWebpackPlugin = require('clean-webpack-plugin');

module.exports = {
    entry: './src/app/app.jsx',
    devtool: 'source-map',
    devServer: {
        contentBase: path.join(__dirname, "dist"),
        hot: true
    },
    module: {
        rules: [
            {
                test: /\.jsx?$/,
                exclude: /node_modules/,
                use: [
                    {
                        loader: "babel-loader",
                        options: {
                            presets: ['es2015', 'react']
                        }
                    }
                ]
            },
            {
                test: /\.css$/,
                use: [
                    'style-loader',
                    'css-loader'
                ],
            }
        ],
    },
    plugins: [
        new HtmlWebpackPlugin({
            template: './src/app/index.html'
        }),
        new webpack.NamedModulesPlugin(),
        new webpack.HotModuleReplacementPlugin()
    ],
    output: {
        path: path.resolve(__dirname, 'dist'),
        filename: 'app.bundle.js'
    }
};

之前:

ERROR in ./src/app/app.jsx Module parse failed: Unexpected token (3:13)

Ater(正确创建的包):


app.bundle.js 424 kB 0 [发射] [大] 主要
app.bundle.js.map 499 kB 0 [发出] 主要