执行cnpm run dev时报以下错误：

ERROR Failed to compile with 1 errors 23:53:49
This dependency was not found:

  • !!vue-style-loader!css-loader?{"sourceMap":true}!../../node_modules/vue-loader
    /lib/style-compiler/index?{"vue":true,"id":"data-v-9fcfedee","scoped":true,"hasI
    nlineConfig":false}!sass-loader?{"sourceMap":true}!../../node_modules/vue-loader
    /lib/selector?type=styles&index=0!./Login.vue in ./src/components/Login.vue

To install it, you can run: npm install --save !!vue-style-loader!css-loader?{"s
ourceMap":true}!../../node_modules/vue-loader/lib/style-compiler/index?{"vue":tr
ue,"id":"data-v-9fcfedee","scoped":true,"hasInlineConfig":false}!sass-loader?{"s
ourceMap":true}!../../node_modules/vue-loader/lib/selector?type=styles&index=0!.
/Login.vue

解决方案：
1、npm install stylus-loader css-loader style-loader --save-dev
2、npm install node-sass sass-loader