项目当dev命令运行时能正常运行，打包后却报错UglifyJs Unexpected token: punc (,)，

> yarn buildCreating an optimized production build...
Failed to compile.Failed to minify the bundle. Error: static/js/main.js from UglifyJs
Unexpected token: punc (,) [static/js/main.js:11913,13]at /Users/busyRobot/workSpace/B/A/scripts/build.js:120:23at /Users/busyRobot/workSpace/B/A/node_modules/webpack/lib/Compiler.js:269:13at Compiler.emitRecords (/Users/busyRobot/workSpace/B/A/node_modules/webpack/lib/Compiler.js:375:38)at /Users/busyRobot/workSpace/B/A/node_modules/webpack/lib/Compiler.js:262:10at /Users/busyRobot/workSpace/B/A/node_modules/webpack/lib/Compiler.js:368:12at next (/Users/busyRobot/workSpace/B/A/node_modules/tapable/lib/Tapable.js:218:11)at Compiler.<anonymous> (/Users/busyRobot/workSpace/B/A/node_modules/webpack/lib/performance/SizeLimitsPlugin.js:99:4)at next (/Users/busyRobot/workSpace/B/A/node_modules/tapable/lib/Tapable.js:220:14)at /Users/busyRobot/workSpace/B/A/node_modules/sw-precache-webpack-plugin/lib/index.js:98:18
Read more here: http://bit.ly/2tRViJ9

但是能顺利打出来，看一下原webpack.prod.conf.js：

 plugins: [
...new webpack.optimize.UglifyJsPlugin({compress: {warnings: false},sourceMap: config.build.productionSourceMap,parallel: true}),
]

经过一番思考后对比其他项目打算换一个压缩插件uglifyjs-webpack-plugin，而不使用webpack内置插件，结果就解决了！

1.在package.json中添加如下插件依赖
“uglifyjs-webpack-plugin”: “^1.1.1”

2.修改文件webpack.prod.conf.js, 替换webpack的压缩插件

//文件开始处添加如下
const UglifyJsPlugin = require("uglifyjs-webpack-plugin");
//插件配置处添加如下plugins: [
...new UglifyJsPlugin({uglifyOptions: {compress: {warnings: false,drop_debugger: true, drop_console: true }},sourceMap: config.build.productionSourceMap,parallel: true}),
...
]

注意把之前的webpack配置的压缩插件注释了。

3.再次打包，成功了。

本文参考文章