• Debug / development mode is fine, but an error occurs after packaging

• webpack.conf.js

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

module.exports = {
    entry: "./src/main.js",
    output: {
        path: path.resolve(__dirname, "./dist"),
        publicPath: "/dist/",
        filename: "build.js"
    },
    module: {
        rules: [
            {
                test: /\.css$/,
                use: [
                    "vue-style-loader",
                    "css-loader"
                ],
            },
            {
                test: /\.scss$/,
                use: [
                    "vue-style-loader",
                    "css-loader",
                    "sass-loader"
                ],
            },
            {
                test: /\.sass$/,
                use: [
                    "vue-style-loader",
                    "css-loader",
                    "sass-loader?indentedSyntax"
                ],
            },
            {
                test: /\.vue$/,
                loader: "vue-loader",
                options: {
                    loaders: {
                        // Since sass-loader (weirdly) has SCSS as its default parse mode, we map
                        // the "scss" and "sass" values for the lang attribute to the right configs here.
                        // other preprocessors should work out of the box, no loader config like this necessary.
                        "scss": [
                            "vue-style-loader",
                            "css-loader",
                            "sass-loader"
                        ],
                        "sass": [
                            "vue-style-loader",
                            "css-loader",
                            "sass-loader?indentedSyntax"
                        ]
                    }
                    // other vue-loader options go here
                }
            },
            {
                test: /\.js$/,
                loader: "babel-loader",
                exclude: /node_modules/
            },
            {
                test: /\.(eot|svg|ttf|woff|woff2)(\?\S*)?$/,
                loader: "file-loader"
            },
            {
                test: /\.(png|jpg|gif|svg)$/,
                loader: "file-loader",
                options: {
                    name: "[name].[ext]?[hash]"
                }
            }
        ]
    },
    resolve: {
        alias: {
            "vue$": "vue/dist/vue.esm.js"
        },
        extensions: ["*", ".js", ".vue", ".json"]
    },
    devServer: {
        historyApiFallback: true,
        noInfo: true,
        overlay: true
    },
    performance: {
        hints: false
    },
    devtool: "-sharpeval-source-map"
}

if (process.env.NODE_ENV === "production") {
    module.exports.devtool = "-sharpsource-map"
    // http://vue-loader.vuejs.org/en/workflow/production.html
    module.exports.plugins = (module.exports.plugins || []).concat([
        new webpack.DefinePlugin({
            "process.env": {
                NODE_ENV: ""production""
            }
        }),
        new webpack.optimize.UglifyJsPlugin({
            sourceMap: true,
            compress: {
                warnings: false
            }
        }),
        new webpack.LoaderOptionsPlugin({
            minimize: true
        })
    ])
}

Please let the known friends tell you the reason, Thanks please () tell