npm run serve 提示Cannot read property 'upgrade' of undefined
一般是proxy的target代理域名问题导致的，如下：
解决方案：
proxy: {
"/remoteDealerReportApi": {
target: 'http://demo-.com.cn', //此域名有问题，会导致运行异常
ws: true,
changeOrigin: true,
pathRewrite: {
"^/remoteDealerReportApi": ""
}
},